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