#include <bits/stdc++.h>
using namespace std;
int main() {
  int q;
  cin >> q;
  while (q--) {
    int n, k, temp;
    cin >> n >> k;
    set<int> s;
    for (int i = 0; i < n; i++) {
      cin >> temp;
      s.insert(temp);
    }
    set<int>::reverse_iterator it;
    int count = 0;
    for (it = s.rbegin(); it != s.rend(); it++) {
      if ((*it - k * count) <= 0) break;
      count++;
    }
    cout << count << "\n";
  }
  return 0;
}
