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