#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
const long long INF = 1e18;
int main() {
  long long t, n, k, m, i;
  cin >> t;
  while (t--) {
    cin >> n >> m >> k;
    vector<long long> a(n, 0);
    for (i = 0; i < (n); i++) {
      cin >> a[i];
    }
    int z = 0;
    for (i = 1; i < (n); i++) {
      if (a[i] - k < 0) {
        m += a[i - 1];
      } else {
        if (a[i] - k <= a[i - 1]) {
          m += a[i - 1] - (a[i] - k);
        } else {
          if ((a[i] - k) - a[i - 1] > m) {
            z = 1;
            break;
          } else {
            m -= (a[i] - k) - a[i - 1];
          }
        }
      }
    }
    if (z == 0) {
      cout << "yes";
    } else {
      cout << "No";
    }
    cout << endl;
  }
  return 0;
}
