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