#include <bits/stdc++.h>
using namespace std;
const int MAXN = (int)1e2 + 7;
int hei[MAXN];
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int N, M, K;
  int T;
  cin >> T;
  while (T--) {
    cin >> N >> M >> K;
    for (int i = (int)1; i <= (int)N; i++) {
      cin >> hei[i];
    }
    bool flag = 0;
    int sum = M;
    for (int i = (int)1; i <= (int)N - 1; i++) {
      int mx = hei[i] - hei[i + 1];
      if (mx > -K) {
        int giv = min(mx + K, hei[i]);
        sum += giv;
      } else {
        int cha = hei[i + 1] - K - hei[i];
        sum -= cha;
      }
      if (sum < 0) flag = 1;
    }
    if (flag)
      cout << "NO" << endl;
    else
      cout << "YES" << endl;
  }
}
