#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long t;
  cin >> t;
  for (long long q = 0; q < t; q++) {
    long long n, m, k;
    cin >> n >> m >> k;
    long long a[n];
    for (long long i = 0; i < n; i++) {
      cin >> a[i];
    }
    long long res = 1;
    for (long long i = 0; i < n - 1; i++) {
      long long w = 0;
      m += a[i] - max(a[i + 1] - k, w);
      if (m < 0) {
        cout << "NO" << endl;
        res = 0;
        break;
      }
    }
    if (res) {
      cout << "YES" << endl;
    }
  }
  return 0;
}
