#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  scanf("%d", &t);
  while (t--) {
    int n, m, k, h0, h1;
    scanf("%d %d %d %d", &n, &m, &k, &h0);
    bool res = true;
    --n;
    while (n--) {
      scanf("%d", &h1);
      if (h0 + m + k < h1) {
        while (getchar() != '\n') {
        };
        res = false;
        break;
      }
      m -= max(h1 - k, 0) - h0;
      h0 = h1;
    }
    printf(res ? "YES\n" : "NO\n");
  }
}
