#include <bits/stdc++.h>
using namespace std;
void fun() {}
long long mod = 1000000000 + 7;
long long powe(long long x, long long y) {
  x = x % mod, y = y % (mod - 1);
  long long ans = 1;
  while (y > 0) {
    if (y & 1) {
      ans = (1ll * x * ans) % mod;
    }
    y >>= 1;
    x = (1ll * x * x) % mod;
  }
  return ans;
}
map<pair<long long, long long>, long long> m;
long long ncr(long long n, long long r) { return n * (n - 1) * (n - 2) / 6; }
int32_t main() {
  fun();
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  long long t, temp;
  long long n, s, k;
  cin >> t;
  while (t--) {
    cin >> n >> s >> k;
    long long a[k];
    long long i;
    long long num;
    for (i = 0; i < k; i++) {
      cin >> num;
      a[i] = num;
    }
    sort(a, a + k);
    long long num1 = INT_MAX, num2 = INT_MAX;
    for (i = s; i >= 1; i--) {
      if (!binary_search(a, a + k, i)) {
        num1 = i;
        break;
      }
    }
    for (i = s; i <= n; i++) {
      if (!binary_search(a, a + k, i)) {
        num2 = i;
        break;
      }
    }
    if (num1 == INT_MAX)
      cout << num2 - s << "\n";
    else if (num2 == INT_MAX)
      cout << s - num1 << "\n";
    else
      cout << min(s - num1, num2 - s) << "\n";
  }
}
