#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  scanf("%d", &t);
  while (t--) {
    int n, bolsa, k;
    scanf("%d%d%d", &n, &bolsa, &k);
    string resp = "YES";
    int v[n];
    for (int i = 0; i < n; i++) {
      scanf("%d", v + i);
    }
    for (int i = 0; i < n - 1; i++) {
      int x = v[i], y = v[i + 1];
      if (x > y) {
        bolsa += abs(x - y);
        x = y;
        bolsa += min(x, k);
      } else if (x <= y) {
        int aux = abs(x - y);
        if (aux <= k) {
          int q = k - aux;
          bolsa += min(x, q);
          continue;
        }
        int qtd = aux - k;
        if (bolsa >= qtd) {
          bolsa -= qtd;
        } else {
          resp = "NO";
          break;
        }
      }
    }
    cout << resp << "\n";
  }
  return 0;
}
