#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int t;
  cin >> t;
  while (t--) {
    long long n, m, k;
    cin >> n >> m >> k;
    long long arr[n];
    for (int i = 0; i < n; i++) cin >> arr[i];
    long long c = m;
    bool f = false;
    for (int i = 1; i < n; i++) {
      if (abs(arr[i] - arr[i - 1]) <= k) {
        if (arr[i - 1] >= arr[i])
          c += min(k, arr[i]) + abs(arr[i] - arr[i - 1]);
        else
          c += min(k, arr[i]) - abs(arr[i] - arr[i - 1]);
      } else if (arr[i] >= arr[i - 1]) {
        c -= (abs(arr[i] - arr[i - 1]) - k);
        if (c < 0) f = true;
      } else
        c += (abs(arr[i] - arr[i - 1]) + min(k, arr[i]));
    }
    if (f)
      cout << "NO" << endl;
    else
      cout << "YES" << endl;
  }
}
