#include<bits/stdc++.h>
using namespace std;
const int M=2e5+5;
int n;
struct node{
	int x,id;
	bool operator <(const node&tmp)const{
		return x<tmp.x; 
	}
}A[M];
int Ans[M],p,q;
long long sum[M];
int val[M],add[M];
void solve(){
	cin>>n;
	for(int i=1;i<=n;i++){
		add[i]=0;
		cin>>A[i].x;
		A[i].id=i;
	}
	cin>>p>>q;
	sort(A+1,A+1+n);
	int len=0;
	for(int i=1;i<=n;i++)sum[i]=sum[i-1]+A[i].x;
	int L=n-1;
	int mx=0;
	for(int i=n;i>=1;i--){
		//(sum[i]-sum[L-1])/(i-L+1) *p/q >= A[i].x
		int l=1,r=i-1,key=i;
		while(l<=r){
			int mid=l+r>>1;
			if((sum[i]-sum[mid-1]) *p >= 1ll*A[i].x*(i-mid+1)*q){
				key=mid;
				r=mid-1;
			}else {
				l=mid+1;
			}
		}
		val[i]=i-key+1;
		mx=max(mx,val[i]);
		//printf("i=%d val=%d\n",i,val[i]);
	}
	for(int i=1;i<=n;i++){
		if(val[i]==mx){
			int k=i-val[i]+1;
			long long s=sum[i]-sum[k];
			int l=1,r=k-1,key=k;
			while(l<=r){
				int mid=l+r>>1;
				if((s+A[mid].x) *p >= 1ll*A[i].x*mx*q){
					key=mid;
					r=mid-1;
				}else {
					l=mid+1; 
				}
			}
			add[key]++;
			add[i+1]--; 
		}
	}
	int res=0;
	for(int i=1;i<=n;i++){
		res+=add[i];
		if(res==0){
			Ans[++len]=A[i].id;
		}
	}
	sort(Ans+1,Ans+1+len);
	cout<<len<<'\n';
	for(int i=1;i<=len;i++){
		cout<<Ans[i]<<' ';
	}
	cout<<'\n';
}
int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	int cas;
	cin>>cas;
	while(cas--){
		solve();
	}
	return 0;
}