#include <bits/stdc++.h>
using namespace std;
long long n, m, k;
vector<long long> h;
bool solve() {
  cin >> n >> m >> k;
  h.resize(n);
  for (int i = 0; i < n; ++i) cin >> h[i];
  for (int i = 1; i < n; ++i) {
    m += h[i - 1] - max(0ll, h[i] - k);
    if (m < 0) return false;
  }
  return true;
}
int main() {
  ios_base::sync_with_stdio(false);
  int t;
  cin >> t;
  while (t--) cout << (solve() ? "YES" : "NO") << "\n";
  return 0;
}
