#include <bits/stdc++.h>
using namespace std;

#define int long long
using i64 = long long;

void solve() {
    int n, k;
    std::cin >> n >> k;

    std::vector<int> a(n + 1);
    std::vector<std::array<int, 2>> b(n + 1);

    for (int i = 1; i <= n; i++) {
        std::cin >> a[i];
    }

    int m;
    std::cin >> m;

    for (int i = 1; i <= n; i++) {
        b[i][0] = a[i] % k;
        if (b[i][0]) {
            b[i][0] = k - b[i][0];
        }
        b[i][1] = a[i];
    }

    std::sort(b.begin() + 1, b.end());

    int ans = 0;
    for (int i = 1; i < n; i++) {
        // std::cout << b[i][0] << ' ' << b[i][1] << '\n';
        if (m >= b[i][0]) {
            m -= b[i][0];
            b[i][1] += b[i][0];
        }        
        ans += b[i][1] / k;
    }

    ans += (b[n][1] + m) / k;

    std::cout << ans << '\n';
}

signed main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);

    int t = 1;
    std::cin >> t;
    while (t --) {
        solve();
    }
}