#include <bits/stdc++.h>
using namespace std;
const double pi = 2 * acos(0);
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int q;
  cin >> q;
  while (q--) {
    int n, r;
    cin >> n >> r;
    set<int> s;
    vector<int> v;
    for (long long i = 0; i < n; i++) {
      int a;
      cin >> a;
      s.insert(a);
    }
    for (auto u : s) v.push_back(u);
    int cnt = 0;
    for (int i = v.size() - 1; i >= 0; i--) {
      if (v[i] - r * cnt > 0) cnt++;
    }
    cout << cnt << "\n";
  }
  return 0;
}
