#include<bits/stdc++.h>
#define ll long long
#define maxn 100005
using namespace std;
ll input(){
	ll ans=0;
	char c=getchar();
	bool flag=0;
	while(c<'0'||c>'9'){
		if(c=='-')flag=1;
		c=getchar();
	}
	while(c>='0'&&c<='9'){
		ans=ans*10+c-'0';
		c=getchar();
	}
	if(flag)ans=-ans;
	return ans;
}
void print(ll ans,char c=0,bool flag=1){
    if(ans<0){
        putchar('-');
        ans=-ans;
    }
    if(ans>=10)print(ans/10,c,0);
    putchar('0'+ans%10);
    if(flag&&c!=0)putchar(c);
}
ll T,n,m,k,w;
ll r[maxn],b[maxn],ans[maxn],tot;
struct lll{
	ll s,t;
	queue<ll>p;
}l[maxn];
void init(){
	tot=0;
	for(ll i=0;i<=m+1;i++){
		while(l[i].p.size())l[i].p.pop();
		l[i].s=l[i].t=0;
	}
}
bool operate(lll a){
	//cout<<"period: "<<a.s<<" to "<<a.t<<endl<<"members: ";
	//for(ll i=0;i<a.p.size();i++)print(a.p[i],' ');
	//cout<<endl;
	if(a.p.size()==0)return 1;
	ll strip[n]={0},cnts=0;
	/*for(ll i=0;i<a.p.size();i++){
		if(i!=0&&strip[cnts]+k-1>=a.p[i])continue;
		strip[++cnts]=a.p[i];
	}*/
	bool flag=0;
	while(a.p.size()){
		ll x=a.p.front();a.p.pop();
	    if(flag&&strip[cnts]+k-1>=x)continue;
		flag=1;
		strip[++cnts]=x;	
	}
	for(ll i=cnts;i>=1;i--){
		if(i==cnts){
			if(strip[i]+k-1>a.t){
				strip[i]=a.t-k+1;//strip[i]+k-1=a.t;
			}
		}
		else{
			if(strip[i]+k-1>=strip[i+1]){
				strip[i]=strip[i+1]-k;//strip[i]+k-1=strip[i+1]-1
			}
		}
	}
	if(strip[1]<a.s)return 0;
	for(ll i=1;i<=cnts;i++){
		ans[++tot]=strip[i];
	}
	return 1;
}
int main(){
    T=input();
    while(T--){
       	n=input();m=input();
    	k=input();w=input();
		init();
    	for(ll i=1;i<=n;i++)
    	r[i]=input();
    	sort(r+1,r+n+1);
    	for(ll i=1;i<=m;i++)
    	b[i]=input();
    	b[0]=0;
    	b[m+1]=w+1;
    	sort(b+1,b+m+1);
    	ll cnta=1,cntb=0,cnt=0;
    	while(1){
    		if(cnta>n){
    			if(b[cntb]<r[cnta-1])cntb++;
    			l[cnt].t=b[cntb]-1;
    			break;
			}
			if(r[cnta]<b[cntb]){
				l[cnt].p.push(r[cnta]);
				cnta++;
			}
			else{
				l[cnt].t=b[cntb]-1;
				l[++cnt].s=b[cntb]+1;
				cntb++;
			}
		}
		for(ll i=1;i<=cnt;i++){
		    if(!operate(l[i])){
		    	print(-1,'\n');
		    	goto END;
			}	
		}
		print(tot,'\n');
		for(ll i=1;i<=tot;i++)print(ans[i],' ');
		putchar('\n');
		END:;
	}
    return 0;
}