#include <bits/stdc++.h>
using namespace std;
int b[105];
int main() {
  int n, t, m, k;
  cin >> t;
  while (t--) {
    cin >> n >> m >> k;
    for (int i = 0; i < n; i++) cin >> b[i];
    for (int i = 0; i < n - 1; i++) {
      if (b[i] + k < b[i + 1])
        m -= (b[i + 1] - b[i] - k);
      else
        m += min(b[i] - b[i + 1] + k, b[i]);
      if (m < 0) {
        puts("NO");
        goto end;
      }
    }
    puts("YES");
  end:
    continue;
  }
  return 0;
}
