#include <bits/stdc++.h>   using namespace std;   bool check(long long int mid, long long int r, vector<long long int>& a) {     long long int d = 0;     long long int cnt = 0;     for (long long int i = a.size() - 1; i >= 0; i--) {       if (a[i] - d <= 0)         continue;       else {         if (cnt < mid) {           d += r;           cnt++;         } else           return false;       }     }     return true;   }   void solve() {     long long int n, r;     cin >> n >> r;     vector<long long int> a(n);     for (long long int i = 0; i < n; i++) cin >> a[i];     sort(a.begin(), a.end());     a.erase(unique(a.begin(), a.end()), a.end());     long long int tl = -1, tr = 1e9;     while (tr - tl > 1) {       long long int mid = (tl + tr) / 2;       if (check(mid, r, a))         tr = mid;       else         tl = mid;     }     cout << tr <<   n ;   }   signed main() {     long long int t;     cin >> t;     for (long long int i = 0; i < t; i++) solve();     return 0;   }   