#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
using pll=pair<ll,ll>;
vector<ll>ve;
ll n,m,k,w;

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0),cout.tie(0);
	int tt;
	cin>>tt;
	while(tt--){
		vector<ll>ans;
		
		cin>>n>>m>>k>>w;
		vector<ll>red,blk;
		for(int i=0;i<n;i++){
			ll x;
			cin>>x;
			red.push_back(x);
		}
		for(int i=0;i<m;i++){
			ll x;
			cin>>x;
			blk.push_back(x);
		}
		blk.push_back(0),blk.push_back(w+1);
		sort(red.begin(),red.end()),sort(blk.begin(),blk.end());
		
		ll flag=0;
		ll posr=0,posb=0;
		while(posb<blk.size()-1){
			ll l=blk[posb],r=blk[posb+1];posb++;
			
			ve.clear();
			for(;posr<red.size();posr++){
				
				if(red[posr]>r)break;
				if(red[posr]>=l&&red[posr]<=r)ve.push_back(red[posr]);
			}
			
			if(ve.empty()){
				continue;
			}
			ll dis=ve[ve.size()-1]-ve[0]+1;
			ll tmp=dis/k;
			if(dis%k)tmp++;
			if(tmp*k>r-l-1){
				flag=1;
				break;
			}
			vector<ll>ans1;
			ll up=min((ll)ve.size(),(r-l-1)/k);
			ll sta=ve[0],ed=sta+k-1,pos=0;
			ll x=0;
			for(ll i=1;i<=up;i++){
				ans1.push_back(sta);
				while(pos<ve.size()&&ve[pos]<=ed){
					pos++;
				}
				if(pos==ve.size()){
					x=i;
					break;
				}
				else {
					sta=ve[pos],ed=sta+k-1;
				}
			}
			ll last=r-1;
			for(int i=ans1.size()-1;i>=0;i--){
				ll sta=ans1[i],ed=sta+k-1;
				if(ed>last){
					ans1[i]-=ed-last;
					last=ans[i]-1;
				}
				else break;
			}
			for(auto it:ans1){
				ans.push_back(it);
			}
			
			
			
		}
		if(flag){
			cout<<-1<<'\n';
			continue;
		}
		cout<<ans.size()<<'\n';
		for(auto it:ans)cout<<it<<' ';cout<<'\n';
		
	}
}