#include <bits/stdc++.h>
#define ff first
#define ss second
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int INF = (int)1e9 + 7;

int main() {
    cin.tie(0); ios_base::sync_with_stdio(0);

    int T; cin >> T;
    while(T--)
    {
        int n; cin >> n;
        int A[n]; for(auto &i : A) cin >> i;
        int p, q; cin >> p >> q;
        pii B[n];
        for(int i = 0; i < n; ++i) B[i] = {A[i], i};
        sort(B, B + n);
        long long ps[n + 1]{};  
        for(int i = 0; i < n; ++i) ps[i + 1] = ps[i] + B[i].ff;
        int L[n];
        for(int r = 1; r <= n; ++r)
        {
            //s: 안된다 e: 된다
            int s = -1, e = r - 1;
            while(s + 1 < e)
            {
                int mid = s + e >> 1;
                if((ps[r] - ps[mid]) * p >= 1ll * B[r - 1].ff * q * (r - mid)) e = mid;
                else s = mid;
            }
            L[r - 1] = e;
        }
        int c = 0;
        for(int i = 0; i < n; ++i) c = max(c, i - L[i] + 1);

        // cout << '\n';
        // cout << c << '\n';
        // for(auto i : L) cout << i << ' '; cout << '\n';

        int R[n];
        for(int i = 0; i < n; ++i) R[i] = i;
        for(int r = c; r <= n; ++r)
        {
            if(L[r - 1] <= r - c)
            {
                R[r - c] = max(R[r - c], r);
                //s: 안된다 e: 된다
                int s = -1, e = r - c;
                while(s + 1 < e)
                {
                    int mid = s + e >> 1;
                    if((ps[r] - ps[r - c + 1] + B[mid].ff) * p >= 1ll * B[r - 1].ff * q * c) e = mid;
                    else s = mid;
                }
                R[e] = max(R[e], r);
            }
        }

        vector<int> ans;
        int mx = 0;
        for(int i = 0; i < n; ++i)
        {
            mx = max(mx, R[i]);
            if(mx == i) ans.push_back(B[i].ss);
            // cout << mx << ' ';
        }
        // cout << '\n';

        sort(ans.begin(), ans.end());
        cout << ans.size() << '\n';
        for(auto i : ans) cout << i + 1 << ' ';
        cout << '\n';
    }
}