#include <iostream>
#include <bits/stdc++.h>
using namespace std;

int main(){

int t;
cin >> t;

while(t--){

  int n,r;
  cin >> n >> r;
  int a[n];

  for(int i = 0; i < n; i++ ){
    cin >> a[i];
  }

  sort(a,a+n,greater<int>());

  int cnt = 0;

  for(int i = 0; i <n; i++){
    if(i > 0 && a[i] == a[i-1]);
    else if(a[i] - cnt*r <= 0);
    else{
      cnt++;
    }
  }

  cout << cnt << endl;
}

}