#include <bits/stdc++.h>
using namespace std;
inline int read() {
  int x = 0, f = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  return x * f;
}
inline long long read1() {
  long long x = 0, f = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  return x * f;
}
const int N = 1e5 + 10;
int h[N];
int main() {
  int T = read();
  while (T--) {
    int n, m, k;
    n = read();
    m = read();
    k = read();
    for (int i = 0; i < (n); i++) h[i] = read();
    int flag = 1;
    for (int i = 0; i < (n - 1); i++) {
      if (m + h[i] >= h[i + 1] - k) {
        int x;
        if (h[i + 1] < k)
          x = 0;
        else
          x = h[i + 1] - k;
        m = m + h[i] - x;
        continue;
      }
      flag = 0;
    }
    if (flag)
      puts("YES");
    else
      puts("NO");
  }
}
