#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using PII = pair<int, int>;
using PLL = pair<ll, ll>;
template <class T>
using V = vector<T>;
template <class T>
using VV = V<V<T>>;
template <typename T>
void view(T e) {
  std::cerr << e << std::endl;
}
template <typename T>
void view(const std::vector<T> &v) {
  for (const auto &e : v) {
    std::cerr << e << " ";
  }
  std::cerr << std::endl;
}
template <typename T>
void view(const std::vector<std::vector<T>> &vv) {
  cerr << endl;
  int cnt = 0;
  for (const auto &v : vv) {
    cerr << cnt << "th : ";
    view(v);
    cnt++;
  }
  cerr << endl;
}
std::ostream &operator<<(std::ostream &dest, __int128_t value) {
  std::ostream::sentry s(dest);
  if (s) {
    __uint128_t tmp = value < 0 ? -value : value;
    char buffer[128];
    char *d = std::end(buffer);
    do {
      --d;
      *d = "0123456789"[tmp % 10];
      tmp /= 10;
    } while (tmp != 0);
    if (value < 0) {
      --d;
      *d = '-';
    }
    int len = std::end(buffer) - d;
    if (dest.rdbuf()->sputn(d, len) != len) {
      dest.setstate(std::ios_base::badbit);
    }
  }
  return dest;
}
template <class T, class K>
bool chmax(T &a, const K b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T, class K>
bool chmin(T &a, const K b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}
const int inf = 1001001001;
int dx[] = {1, 0, -1, 0};
int dy[] = {0, 1, 0, -1};
ll rddiv(ll a, ll b) { return a / b - ((a ^ b) < 0 && a % b); }
ll power(ll a, ll p) {
  ll ret = 1;
  while (p) {
    if (p & 1) {
      ret = ret * a;
    }
    a = a * a;
    p >>= 1;
  }
  return ret;
}
ll modpow(ll a, ll p, ll mod) {
  ll ret = 1;
  while (p) {
    if (p & 1) {
      ret = ret * a % mod;
    }
    a = a * a % mod;
    p >>= 1;
  }
  return ret;
}
ll rudiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); }
const ll mod = 1000000007;
int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  int t;
  cin >> t;
  while (t--) {
    int n, r;
    cin >> n >> r;
    V<int> x(n);
    for (ll i = 0; i < n; ++i) cin >> x[i];
    sort((x).begin(), (x).end());
    x.erase(unique((x).begin(), (x).end()), x.end());
    int ans = 0;
    int cnt = 0;
    for (ll i = ((int)(x).size()); i--;) {
      if (x[i] - cnt <= 0) break;
      ans++, cnt += r;
    }
    cout << ans << endl;
  }
}
