#include <bits/stdc++.h>
using namespace std;
const long double EPS = 3e-16;
const long long MAXN = (1e4 + 2);
const long long INF = 1e9 + 7;
void file() {
  freopen(
      "choose"
      ".in",
      "r", stdin);
  if (0)
    freopen(
        "choose"
        ".out",
        "w", stdout);
}
bool TPrime(long long n) {
  if (n < 2) return 0;
  for (long long i = 2; i * i <= n; i++) {
    if (n % i == 0) return 0;
  }
  return 1;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int q;
  cin >> q;
  int n, r;
  while (q--) {
    cin >> n >> r;
    set<int> pew;
    for (int i = 1, x; i <= n; i++) {
      cin >> x;
      pew.insert(x);
    }
    long long ans = 0;
    set<int>::iterator it = pew.end();
    it--;
    for (; it != pew.begin(); it--) {
      ans += ((*it) - ans * r > 0);
    }
    ans += ((*it) - ans * r > 0);
    cout << ans;
    cout << endl;
  }
  return 0;
}
