#include<bits/stdc++.h>
using namespace std;
using ll=long long;

void solve(){
	int n,m,k,w;
	cin>>n>>m>>k>>w;
	vector<int> a(n);
	vector<int> b(m);
	for(int i=0;i<n;i++){
		cin>>a[i];
	}
	for(int i=0;i<m;i++){
		cin>>b[i];
	}
	sort(a.begin(),a.end());
	sort(b.begin(),b.end());
	vector<array<ll,2>> ans;
	for(int i=0;i<n;i++){
		if(!ans.empty()){
			auto [lsl,lsr]=ans.back();
			if(a[i]<=lsr){
				continue;
			}
		}
		ll l=a[i],r=a[i]+k-1;
		r=min(r,1ll*w);
		ans.push_back({l,r});
	}
	int nn=ans.size()-1;
	for(int i=m-1;i>=0;i--){
		auto [l,r]=ans[nn];
		if(b[i]>=l&&b[i]<=r){
			l=max(1ll,l-(r-(b[i]-1)));
			r=b[i]-1;
			if(l==ans[nn-1][1]&&nn!=0){
				ans[nn-1][0]--;
				ans[nn-1][1]--;
			}else if(l==ans[nn-1][1]&&nn==0){
				cout<<"-1\n";
				return;
			}
			ans[nn][0]=l;
			ans[nn][1]=r;
		}else{
			if(l>b[i]){
				nn--;
				i++;
				if(nn<0){
					break;
				}
			}
		}
	}
	if(b[0]>=ans[0][0]&&b[0]<=ans[0][1]){
		cout<<"-1\n";
		return;
	}
	//cout<<ans.size()<<"\n";
	nn=ans.size()-1;
	for(int i=0;i<nn;i++){
		if(ans[i][1]==ans[i+1][0]||ans[i][1]-ans[i][0]+1!=k){
			cout<<"-1\n";
			return;
		}
	}
	if(ans[nn][1]-ans[nn][0]+1!=k){
		cout<<"-1\n";
		return;
	}
	cout<<ans.size()<<"\n";
	for(auto [l,r]:ans){
		cout<<l<<" ";
	}
	cout<<"\n";

}
int main(){
	ios::sync_with_stdio(0),cin.tie(0);
	int _=1;cin>>_;
	while(_--) solve();
	return 0;
}