#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  for (int j = 0; j < t; j++) {
    long long int n, m, k;
    bool y = true;
    cin >> n >> m >> k;
    long long int a[n];
    for (long long int i = 0; i < n; i++) {
      cin >> a[i];
    }
    for (int i = 0; i < n - 1; i++) {
      if (a[i + 1] - k < 0)
        m = m + a[i];
      else
        m = m + a[i] - (a[i + 1] - k);
      if (m < 0) {
        y = false;
        break;
      }
    }
    if (y)
      cout << "YES" << endl;
    else
      cout << "NO" << endl;
  }
  return 0;
}
