#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, i, j, t;
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> t;
  while (t--) {
    int b, k;
    cin >> n >> b >> k;
    int arr[n];
    for (i = 0; i < n; i++) cin >> arr[i];
    int flag = 1;
    for (i = 0; i < n - 1; i++) {
      if (arr[i] >= arr[i + 1]) {
        b += arr[i] - arr[i + 1] + min(k, arr[i + 1]);
      } else if (arr[i + 1] > arr[i] + k) {
        b -= arr[i + 1] - arr[i] - k;
        if (b < 0) {
          flag = 0;
          break;
        }
      } else {
        b += min(arr[i], arr[i] + k - arr[i + 1]);
      }
    }
    if (flag)
      cout << "YES\n";
    else
      cout << "NO\n";
  }
  return 0;
}
