#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define int ll
#define rep(i,a,b) for(int i = a; i < (b); i++)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define PB push_back
#define FS first
#define SD second
#define cmx(x,y) x = max(x,y)
#define cmn(x,y) x = min(x,y)
#define ary(k) array<int,k>
typedef pair<int,int> pii;
typedef vector<int> vi;

pii tab[1000002];
int pref[1000002];
int lg[1000002], res[1000002];

void fun() {
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> tab[i].FS;
        tab[i].SD = i;
    }
    sort(tab+1, tab+n+1);
    for (int i = 1; i <= n; i++) {
        pref[i] = pref[i-1] + tab[i].FS;
        res[i] = 0;
    }
    int p, q;
    cin >> p >> q;
    int longest = 0;
    for (int i = 1; i <= n; i++) {
        int pocz = 1, kon = i;
        while (pocz < kon) {
            int sr = (pocz + kon) / 2;
            int sum = pref[i] - pref[sr - 1];
            // tab[i] <= sum / (ile) * (p/q)
            if (tab[i].FS * (i - sr + 1) * q <= sum * p) {
                kon = sr;
            } else {
                pocz = sr + 1;
            }
        }
        lg[i] = pocz;
//        cerr << i << " " << lg[i] << "\n";
        cmx(longest, i - pocz + 1);
    }
//    cerr << longest << "\n";
    for (int i = 1; i <= n; i++) {
        if (i - lg[i] + 1 < longest)
            continue;
        int pocz = 1, kon = lg[i];
        while (pocz < kon) {
            int sr = (pocz + kon) / 2;
            int sum = pref[i] - pref[lg[i] - 1] - tab[lg[i]].FS + tab[sr].FS;
            // tab[i] <= sum / (ile) * (p/q)
            if (tab[i].FS * (i - sr + 1) * q <= sum * p) {
                kon = sr;
            } else {
                pocz = sr + 1;
            }
        }
        res[pocz]++;
        res[i+1]--;
    }
    vi ans;
    for (int i = 1; i <= n; i++) {
        res[i] += res[i-1];
        if (res[i] == 0)
            ans.PB(tab[i].SD);
    }
    sort(all(ans));
    cout << sz(ans) << "\n";
    for (auto a : ans) {
        cout << a << " ";
    }
    cout << "\n";
}

signed main(){
	cin.tie(0)->sync_with_stdio(0); cin.exceptions(cin.failbit);
    int z;
    cin >> z;
    while (z--) fun();
}