#include <bits/stdc++.h>
using namespace std;
int n, m, k;
int main() {
  int T;
  scanf("%d", &T);
  while (T--) {
    scanf("%d%d%d", &n, &m, &k);
    int cnt = m;
    int pre = 0;
    int pd = 0;
    scanf("%d", &pre);
    for (int i = 2; i <= n; i++) {
      int x;
      scanf("%d", &x);
      if (pd == 1) continue;
      if (x - k > pre) {
        cnt -= (x - k - pre);
        if (cnt < 0) {
          printf("NO\n");
          pd = 1;
        }
      }
      if (x - pre <= k) {
        cnt += (pre - max(x - k, 0));
      }
      pre = x;
    }
    if (!pd) printf("YES\n");
  }
  return 0;
}
