#include<bits/stdc++.h>
using namespace std;
const int maxn=1e5+10;
struct cell{
	int col;
	int pos;
	bool operator <(const cell &b){
		return pos<b.pos;
	}
}c[maxn];
int ans[maxn];
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int t;
	cin>>t;
	while(t--){
		int n,m,k,w;
		cin>>n>>m>>k>>w;
		for(int i=1;i<=n;i++){
			cin>>c[i].pos;
			c[i].col=1;
		}
		for(int i=1;i<=m;i++){
			cin>>c[n+i].pos;
			c[n+i].col=2;
		}
		int adjustment,st=0,strip_cnt=0,strip_cnt_rec=0;
		sort(c+1,c+1+(n+m));
		c[n+m+1].pos=w+1;
		c[n+m+1].col=2;
		bool jd=1;
		for(int i=1;i<=n+m+1;i++){
			if(c[i].col==2){
				if(c[i].pos<=st-adjustment){//must be covered by a strip no matter what
					jd=0;
					break;
				}
				else if(c[i].pos<=st){
					//cout<<"Found!"<<endl;
					for(int j=strip_cnt;j>strip_cnt_rec;j--){
						//cout<<"Adjustting for strip No."<<j<<endl;
						ans[j]-=st-c[i].pos+1;
					}
				}
				adjustment=0;
				st=c[i].pos;
				strip_cnt_rec=strip_cnt;
			}
			else{
				if(c[i].pos-st-1<0)continue;
				adjustment+=c[i].pos-1-st;
				if(adjustment>=k){
					adjustment%=k;
					strip_cnt_rec=strip_cnt;
				}
				ans[++strip_cnt]=c[i].pos;
				st=c[i].pos+k-1;
			}
		}
		if(!jd){
			cout<<-1<<endl;
		}
		else{
			cout<<strip_cnt<<endl;
			for(int i=1;i<=strip_cnt;i++){
				cout<<ans[i]<<" ";
			}
			cout<<endl;
		}
	}
	return 0;
}
/*
1
4 1 2 11
8 6 4 10
9
*/