#include<bits/stdc++.h>
using namespace std;
#define int long long
const int inf=1e17;
void solve(){
	int n,m,w,k;cin>>n>>m>>k>>w;
	vector<int>red,blc;
	for(int i=1;i<=n;i++){
		int p;cin>>p;
		red.push_back(p);
	}
	
	for(int i=1;i<=m;i++){
		int p;cin>>p;
		blc.push_back(p);
	}
	blc.push_back(0);blc.push_back(w+1);
	sort(red.begin(),red.end());
	sort(blc.begin(),blc.end());
	int last=0;
//	cout<<"se-------------\n";
//	for(auto p:red)cout<<p<<" ";
//	cout<<'\n';
//	for(auto p:blc)cout<<p<<" ";cout<<'\n';
	vector<int>ans;
	for(int i=0;i<n;i++){
		int p =red[i];
	//	cout<<" p:"<<p<<" last:"<<last<<"\n";
		
		if(last>=p)continue;
		last=p+k-1;
		int q = *lower_bound(blc.begin(),blc.end(),p);
		if(p+k-1>=q){
			if(q-k>last&&q-k>*--lower_bound(blc.begin(),blc.end(),q)){
				ans.push_back(q-k);
				continue;
			}
			int last=q-k,p = *--lower_bound(blc.begin(),blc.end(),q);
			if(q-p-1<k){
				cout<<-1<<'\n';
				return;
			}
			
			 for(int i=(int)ans.size()-1;i>=0;i--){
				int idx = ans[i];
				if(idx<p)break;
				if(idx+k-1>=last){
					last = last-k;
					ans[i]=last;
				}else break;
				if(last<=p){
					cout<<-1<<'\n';
					return;
				}
				
			}
			ans.push_back(q-k);
			
			continue;
		}
		
		last=p+k-1;
		ans.push_back(p);
	}
	cout<<ans.size()<<'\n';
	if(ans.size()==0)return;
	for(auto p:ans)cout<<p<<" ";
	cout<<'\n';
	
	
}
signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0);cout.tie(0);
	int t=1;
	cin>>t;
	while(t--){
		solve();
	}
}