#include<bits/stdc++.h>
using namespace std;
constexpr int maxn=2e5+5;
int n;
typedef long long ll;
ll a[maxn],sum[maxn],p,q;
int id[maxn];
inline void solve(){
    cin>>n;
    for(int i=1;i<=n;i++) cin>>a[i],id[i]=i;
    sort(id+1,id+n+1,[&](int x,int y){return a[x]<a[y];});
    sort(a+1,a+n+1);
    for(int i=1;i<=n;i++)sum[i]=sum[i-1]+a[i];
    cin>>p>>q;
    int mx=0,L=0,R=0;
    vector<pair<int,int>> sb;
    for(int i=1;i<=n;i++){
        int l=0,r=i-1;
        auto chk=[&](int d){
            return (sum[i]-sum[d])*p>=q*a[i]*(i-d);
        };
        while(l<r){
            int mid=l+r>>1;
            if(chk(mid)) r=mid;
            else l=mid+1;
        }
        if(i-r>mx){
            mx=i-r;L=r,R=i+1;
            sb.clear();
        }
        else if(i-r==mx){
            if(l>=R) sb.emplace_back(R,l);
            R=i+1;
        }
    }
    vector<int> v;
    for(auto [l,r]:sb) for(int i=l;i<=r;i++) v.push_back(id[i]);
    for(int i=1;i<=L;i++) v.push_back(id[i]);
    for(int i=R;i<=n;i++) v.push_back(id[i]);
    sort(v.begin(),v.end());
    cout<<v.size()<<'\n';
    for(auto x:v) cout<<x<<' ';cout<<'\n';
}
int main(){
    std::ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    int t;cin>>t;
    while(t--) solve();
}