#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main() {
    int tt; cin >> tt;
    while (tt--) {
        int n; cin >> n;
        vector<pair<int, int>> a(n + 1);
        for (int i = 1; i <= n; i++) {
            cin >> a[i].first;
            a[i].second = i;
        }
        int p, q; cin >> p >> q;
        int r = 1;
        int sum = 0;
        int mx = 0;
        sort(a.begin() + 1, a.begin() + 1 + n);
        for (int i = 1; i <= n; i++) {
            r = max(r, i + 1);
            sum += a[i].first;
            while (r <= n && a[r].first * q * (r - i + 1) <= (a[r].first + sum) * p) {
                sum += a[r].first;
                r++;
            }
            mx = max(mx, r - i);
            sum -= a[i].first;
        }
        sum = 0;
        for (int i = 1; i <= mx; i++) {
            sum += a[i].first;
        }
        vector<int> ans;
        for (int i = mx; i <= n; i++) {
            if (a[i].first * q * mx > sum * p) {
                ans.push_back(a[i].second);
            }
            if (i == n) break;
            sum -= a[i - mx + 1].first;
            sum += a[i + 1].first;
        }
        cout << ans.size() << '\n';
        for (int i = 0; i < ans.size(); i++) {
            cout << ans[i] << ' ';
        }
        cout << '\n';
    }
    return 0;
}
/*
3
4
1 2 3 4
3 2
5
1 15 2 5 1
2 1
5
1 2 3 1000 10000 
4 3
*/