description: A tree is an undirected connected graph without cycles.
  
  You are given a tree of n vertices. Find the number of ways to choose exactly k vertices in this tree (i. e. a k-element subset of vertices) so that all pairwise distances between the selected vertices are equal (in other words, there exists an integer c such that for all u, v (u ≠ v, u, v are in selected vertices) d_{u,v}=c, where d_{u,v} is the distance from u to v).
  
  Since the answer may be very large, you need to output it modulo 10^9 + 7.
  
  Input
  
  The first line contains one integer t (1 ≤ t ≤ 10) — the number of test cases. Then t test cases follow.
  
  Each test case is preceded by an empty line.
  
  Each test case consists of several lines. The first line of the test case contains two integers n and k (2 ≤ k ≤ n ≤ 100) — the number of vertices in the tree and the number of vertices to be selected, respectively. Then n - 1 lines follow, each of them contains two integers u and v (1 ≤ u, v ≤ n, u ≠ v) which describe a pair of vertices connected by an edge. It is guaranteed that the given graph is a tree and has no loops or multiple edges.
  
  Output
  
  For each test case output in a separate line a single integer — the number of ways to select exactly k vertices so that for all pairs of selected vertices the distances between the vertices in the pairs are equal, modulo 10^9 + 7 (in other words, print the remainder when divided by 1000000007).
  
  Example
  
  Input
  
  
  3
  
  4 2
  1 2
  2 3
  2 4
  
  3 3
  1 2
  2 3
  
  5 3
  1 2
  2 3
  2 4
  4 5
  
  
  Output
  
  
  6
  0
  1
solution: import java.io.*;
  import java.util.*;
  
  import static java.lang.Math.*;
  import static java.util.Arrays.sort;
  import static java.util.Comparator.comparingInt;
  
  public class Round {
      FastScanner in;
      PrintWriter out;
  
      private void solve() throws IOException {
          solveF();
      }
  
      private void solve_a() throws IOException {
          int n = in.nextInt();
          out.println(n / 3 + (n % 3 == 1 ? 1 : 0) + " " + (n / 3 + (n % 3 == 2 ? 1 : 0)));
      }
  
      private void solve_b1() throws IOException {
          char[] s = in.next().toCharArray();
          int n = s.length, k = 2, alpha = 'z' - 'a' + 1;
  
          ArrayList<Integer>[] pos = new ArrayList[alpha];
          for (int i = 0; i < alpha; i++)
              pos[i] = new ArrayList<>();
  
          for (int i = 0; i < n; i++)
              pos[s[i] - 'a'].add(i);
  
          int max_cnt = 0;
          for (int i = 0; i < alpha; i++)
              max_cnt += min(k, pos[i].size());
  
          max_cnt -= max_cnt % k;
  
          out.println(max_cnt / k);
      }
  
      private void solve_b2() throws IOException {
          int n = in.nextInt(), k = in.nextInt();
  
          ArrayList<Integer>[] pos = new ArrayList[n];
          for (int i = 0; i < n; i++)
              pos[i] = new ArrayList<>();
  
          for (int i = 0; i < n; i++)
              pos[in.nextInt() - 1].add(i);
  
          int max_cnt = 0;
          for (int i = 0; i < n; i++)
              max_cnt += min(k, pos[i].size());
  
          max_cnt -= max_cnt % k;
  
          int[] c = new int[n];
          int cur = 0;
  
          for (int i = 0; i < n; i++) {
              if (pos[i].size() >= k) {
                  for (int j = 0; j < k; j++) {
                      c[pos[i].get(j)] = cur % k + 1;
                      cur++;
                  }
              }
          }
  
          for (int i = 0; i < n && cur < max_cnt; i++) {
              if (pos[i].size() < k) {
                  for (int j = 0; j < pos[i].size() && cur < max_cnt; j++) {
                      c[pos[i].get(j)] = cur % k + 1;
                      cur++;
                  }
              }
          }
  
          for (int i = 0; i < n; i++)
              out.print(c[i] + " ");
          out.println();
      }
  
      private void solve_c() throws IOException {
          int n = in.nextInt();
          int[][] cnt = new int[n][6];
          for (int i = 0; i < n; i++)
              for (char c : in.next().toCharArray()) {
                  cnt[i][c - 'a']++;
                  cnt[i][5]++;
              }
  
          int ans = 0;
          for (int i = 0; i < 5; i++) {
              int finalI = i;
              sort(cnt, comparingInt(o -> -(o[finalI] - (o[5] - o[finalI]))));
              int cnti = 0, cnto = 0;
              for (int j = 0; j < n; j++) {
                  cnti += cnt[j][i];
                  cnto += cnt[j][5] - cnt[j][i];
                  if (cnti > cnto)
                      ans = max(ans, j + 1);
                  else
                      break;
              }
          }
          out.println(ans);
      }
  
      private void solve_d1() throws IOException {
          int n = in.nextInt(), m = in.nextInt();
          int horizontal = in.nextInt(), vertical = n * m / 2 - horizontal;
  
          if (n % 2 == 1)
              horizontal -= m / 2;
  
          if (m % 2 == 1)
              vertical -= n / 2;
  
          out.println(vertical < 0 || vertical % 2 == 1 || horizontal < 0 || horizontal % 2 == 1 ? "NO" : "YES");
      }
  
      private void solve_d2() throws IOException {
          int n = in.nextInt(), m = in.nextInt();
          int horizontal = in.nextInt(), vertical = n * m / 2 - horizontal;
  
          char[][] ans = new char[n][m];
          TreeMap<Character, Character> pair = new TreeMap<>();
          for (char i = 'a'; i < 'z'; i += 2) {
              pair.put(i, (char) (i + 1));
              pair.put((char) (i + 1), i);
          }
          int si = 0, sj = 0;
  
          if (n % 2 == 1) {
              horizontal -= m / 2;
              char c = 'a';
              for (int j = 0; j < m; j += 2) {
                  ans[si][j] = ans[si][j + 1] = c;
                  c = pair.get(c);
              }
              si++;
          }
  
          if (m % 2 == 1) {
              vertical -= n / 2;
              char c = 'a';
              for (int i = 0; i < n; i += 2) {
                  ans[i][sj] = ans[i + 1][sj] = c;
                  c = pair.get(c);
              }
              sj++;
          }
  
          main:
          for (int i = si; i < n; i += 2) {
              for (int j = sj; j < m; j += 2) {
                  for (char c : pair.keySet()) {
                      if ((i == 0 || (ans[i - 1][j] != c && ans[i - 1][j] != pair.get(c))) && (j == 0 || (ans[i][j - 1] != c && ans[i][j - 1] != pair.get(c)))) {
                          if (horizontal > 0) {
                              ans[i][j] = ans[i][j + 1] = c;
                              ans[i + 1][j] = ans[i + 1][j + 1] = pair.get(c);
                              horizontal -= 2;
                          } else if (vertical > 0) {
                              ans[i][j] = ans[i + 1][j] = c;
                              ans[i][j + 1] = ans[i + 1][j + 1] = pair.get(c);
                              vertical -= 2;
                          } else {
                              break main;
                          }
                          break;
                      }
                  }
              }
          }
  
          if (vertical < 0 || vertical % 2 == 1 || horizontal < 0 || horizontal % 2 == 1) {
              out.println("NO");
          } else {
              out.println("YES");
  
              for (int i = 0; i < n; i++) {
                  out.println(new String(ans[i]));
              }
          }
      }
  
      private void solveE() throws IOException {
          int n = in.nextInt(), k = in.nextInt();
  
          int[] needRemove = new int[n];
          for (int pos = 0; pos < n; pos++)
              needRemove[pos] = pos - (in.nextInt() - 1);
  
          out.println(Arrays.toString(needRemove));
  
          int[][] dp = new int[n + 1][n + 1];
          int ans = Integer.MAX_VALUE / 1613;
          for (int pos = n - 1; pos >= 0; pos--) {
              if (needRemove[pos] >= 0 && needRemove[pos] <= pos) {
                  for (int pos2 = pos + 1; pos2 < n; pos2++) {
                      dp[needRemove[pos]][pos2]++;
  
                  }
              }
          }
      }
  
      int n, k;
      ArrayList<Integer>[] graph;
      long ans, mod = 1000_000_007L;
      long[][] downCnt, fullCnt;
  
      private void dfs(int v, int p) {
          for (int u : graph[v])
              if (u != p)
                  dfs(u, v);
  
          downCnt[v][0]++;
          for (int u : graph[v])
              if (u != p)
                  for (int i = 1; i < n; i++)
                      downCnt[v][i] += downCnt[u][i - 1];
      }
  
      private void dfs1(int v, int p) {
          System.arraycopy(downCnt[v], 0, fullCnt[v], 0, n);
          for (int u : graph[v])
              if (u == p)
                  for (int dist = n - 1; dist > 0; dist--)
                      fullCnt[v][dist] += fullCnt[u][dist - 1] - (dist >= 2 ? downCnt[v][dist - 2] : 0);
  
          for (int u : graph[v])
              if (u != p)
                  dfs1(u, v);
      }
  
      private void dfs2(int v, int p) {
          for (int u : graph[v])
              if (u != p)
                  dfs2(u, v);
  
          long[][][] dp = new long[n][graph[v].size()][k + 1];
          for (int dist = 1; dist < n; dist++) {
              for (int i = 0; i < graph[v].size(); i++) {
                  int u = graph[v].get(i);
                  dp[dist][i][0] = 1;
                  for (int j = 1; j <= min(i + 1, k); j++) {
                      dp[dist][i][j] = ((i == 0 ? 0 : dp[dist][i - 1][j]) +
                              (i == 0 ? 1 : dp[dist][i - 1][j - 1]) *
                                      (u == p ? fullCnt[u][dist - 1] - (dist < 2 ? 0 : downCnt[v][dist - 2]) + mod
                                              : downCnt[u][dist - 1]) % mod) % mod;
                  }
              }
              /*if (dp[dist][graph[v].size() - 1][k] != 0) {
                  out.println("v = " + (v + 1) + " | dist = " + dist + " | k = " + k + " -> " + dp[dist][graph[v].size() - 1][k]);
                  for (int i = 0; i < graph[v].size(); i++) {
                      int u = graph[v].get(i);
                      out.println("u = " + (u + 1) + " -> " + (u == p ?
                              fullCnt[u][dist - 1] + " - " + (dist < 2 ? 0 : downCnt[v][dist - 2]) + " = " + (fullCnt[u][dist - 1] - (dist < 2 ? 0 : downCnt[v][dist - 2]))
                              : downCnt[u][dist - 1] + ""));
                  }
              }*/
              ans = (ans + dp[dist][graph[v].size() - 1][k]) % mod;
          }
      }
  
      private void solveF() throws IOException {
          n = in.nextInt();
          k = in.nextInt();
  
          graph = new ArrayList[n];
          for (int i = 0; i < n; i++)
              graph[i] = new ArrayList<>();
  
          for (int i = 0; i < n - 1; i++) {
              int v = in.nextInt() - 1, u = in.nextInt() - 1;
              graph[v].add(u);
              graph[u].add(v);
          }
  
          if (k == 2) {
              out.println(n * (n - 1) / 2);
              return;
          }
  
          ans = 0;
          downCnt = new long[n][n];
          dfs(0, -1);
  
          // print(downCnt);
  
          fullCnt = new long[n][n];
          dfs1(0, -1);
  
          // print(fullCnt);
  
          dfs2(0, -1);
          out.println(ans);
      }
  
      private void print(long[][] cnt) {
          for (int i = 0; i < n; i++) {
              out.print(i + 1 + ":");
              for (int j = 0; j < n; j++) {
                  out.print(" " + cnt[i][j]);
              }
              out.println();
          }
      }
  
      class FastScanner {
          StringTokenizer st;
          BufferedReader br;
  
          FastScanner(InputStream s) {
              br = new BufferedReader(new InputStreamReader(s));
          }
  
          String next() throws IOException {
              while (st == null || !st.hasMoreTokens())
                  st = new StringTokenizer(br.readLine());
              return st.nextToken();
          }
  
          int nextInt() throws IOException {
              return Integer.parseInt(next());
          }
  
          long nextLong() throws IOException {
              return Long.parseLong(next());
          }
  
          double nextDouble() throws IOException {
              return Double.parseDouble(next());
          }
      }
  
      private void run() throws IOException {
          in = new FastScanner(System.in);
          out = new PrintWriter(System.out);
  
          for (int t = in.nextInt(); t-- > 0; )
              solve();
  
          out.flush();
          out.close();
      }
  
      public static void main(String[] args) throws IOException {
          new Round().run();
      }
  }
  