#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }
long long powmod(long long a, long long b, long long MOD) {
  if (a == 0ll) {
    return 0ll;
  }
  a %= MOD;
  long long ans = 1;
  while (b) {
    if (b & 1) {
      ans = ans * a % MOD;
    }
    a = a * a % MOD;
    b >>= 1;
  }
  return ans;
}
long long poww(long long a, long long b) {
  if (a == 0ll) {
    return 0ll;
  }
  long long ans = 1;
  while (b) {
    if (b & 1) {
      ans = ans * a;
    }
    a = a * a;
    b >>= 1;
  }
  return ans;
}
void Pv(const vector<int> &V) {
  int Len = int(V.size());
  for (int i = 0; i < Len; ++i) {
    printf("%d", V[i]);
    if (i != Len - 1) {
      printf(" ");
    } else {
      printf("\n");
    }
  }
}
void Pvl(const vector<long long> &V) {
  int Len = int(V.size());
  for (int i = 0; i < Len; ++i) {
    printf("%lld", V[i]);
    if (i != Len - 1) {
      printf(" ");
    } else {
      printf("\n");
    }
  }
}
inline long long readll() {
  long long tmp = 0, fh = 1;
  char c = getchar();
  while (c < '0' || c > '9') {
    if (c == '-') fh = -1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') tmp = tmp * 10 + c - 48, c = getchar();
  return tmp * fh;
}
inline int readint() {
  int tmp = 0, fh = 1;
  char c = getchar();
  while (c < '0' || c > '9') {
    if (c == '-') fh = -1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') tmp = tmp * 10 + c - 48, c = getchar();
  return tmp * fh;
}
void pvarr_int(int *arr, int n, int strat = 1) {
  if (strat == 0) {
    n--;
  }
  for (int i = strat; i <= n; i++) {
    printf("%d%c", arr[i], i == n ? '\n' : ' ');
  }
}
void pvarr_LL(long long *arr, int n, int strat = 1) {
  if (strat == 0) {
    n--;
  }
  for (int i = strat; i <= n; i++) {
    printf("%lld%c", arr[i], i == n ? '\n' : ' ');
  }
}
const int maxn = 1000010;
const int inf = 0x3f3f3f3f;
int n;
long long k;
long long a[maxn];
long long b[maxn];
long long c[maxn];
int st1[maxn][25];
void init(int n) {
  for (int i = 0; i < n; i++) {
    st1[i][0] = c[i + 1];
  }
  for (int i = 1; (1 << i) <= n; i++) {
    for (int j = 0; j + (1 << i) - 1 < n; j++) {
      st1[j][i] = max(st1[j][i - 1], st1[j + (1 << (i - 1))][i - 1]);
    }
  }
}
int querysmax(int l, int r) {
  if (l > r) return 0;
  l--;
  r--;
  int k = (int)(log((double)(r - l + 1)) / log(2.0));
  return max(st1[l][k], st1[r - (1 << k) + 1][k]);
}
int main() {
  int t;
  t = readint();
  while (t--) {
    n = readint();
    k = readint();
    std::vector<int> v;
    for (int i = 1; i <= n; i++) {
      a[i] = readint();
    }
    for (int i = 1; i <= n; i++) {
      b[i] = readint();
    }
    sort(a + 1, a + 1 + n);
    int l = 1;
    int r = 1;
    for (; l <= n; ++l) {
      while (r < n && a[r + 1] - a[l] <= k) {
        r++;
      }
      c[l] = r - l + 1;
    }
    init(n);
    long long ans = 0;
    for (int i = 1; i <= n; i++) {
      long long now = c[i];
      int pos = upper_bound(a + 1, a + 1 + n, a[i] + k) - a;
      now += querysmax(pos, n);
      ans = max(ans, now);
    }
    printf("%lld\n", ans);
  }
  return 0;
}
