#include <map>
#include <set>
#include <queue>
#include <deque>
#include <cmath>
#include <vector>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <unordered_map>
using namespace std;
#define fi first
#define se second
#define u1 (u<<1)
#define u2 (u<<1|1)
#define pb emplace_back
#define pp pop_back()
#define int long long
#define laile cout<<"laile"<<endl
#define lowbit(x) ((x)&(-x))
#define double long double
#define sf(x) scanf("%lld",&x)
#define sff(x,y) scanf("%lld %lld",&x,&y)
#define sd(x) scanf("%Lf",&x)
#define sdd(x,y) scanf("%Lf %Lf",&x,&y)
#define _for(i,n) for(int i=0;i<(n);++i)
#define _rep(i,a,b) for(int i=(a);i<=(b);++i)
#define _pre(i,a,b) for(int i=(a);i>=(b);--i)
#define all(x) (x).begin(), (x).end()
#define IOS ios::sync_with_stdio(false);cin.tie(0);cout.tie(0)
typedef unsigned long long ULL;
typedef pair<int,int>PII;
typedef pair<double,double>PDD;
const int N=1e6+10,INF=4e18;
int n,m,k,w;
int a[N],b[N];
vector<int>res;
bool deal(vector<int>&v,int l,int r)
{
	int R=v.back()+k-1;
	vector<int>offset;
	int needdis=R-r+1;
//	cout<<"nedis"<<needdis<<endl;
	int pre=l;
//	cout<<"v"<<endl;
//	cout<<l<<"-----";
	for(auto i:v)
	{
//		cout<<i<<" ";
		offset.pb(i-pre-1);
		pre=i+k-1;
	}
//	cout<<endl;
//	cout<<"offs/et:"<<" ";
//	for(auto i:offset)cout<<i<<" ";
//	cout<<endl;
//	cout<<"-----"<<r;
//	cout<<endl;
	bool bl=false;
	for(int i=(int)v.size()-1;i>=0;i--)
	{
		if(!bl)
		{
			if(needdis>offset[i])needdis-=offset[i];
			else 
			{
				int now=v[i]-needdis;
				needdis=0;
				while(now<r)
				{
					res.pb(now);
					now+=k;
				}
				bl=true;
			}
		}
		else 
			res.pb(v[i]);
	}
//	cout<<"needdis="<<needdis<<endl;
	return needdis<=0;
}
void solve()
{
	cin>>n>>m>>k>>w;
	res.clear();
	_rep(i,1,n)cin>>a[i];
	_rep(i,1,m)cin>>b[i];
	sort(a+1,a+1+n);
	sort(b+1,b+1+m);
	b[m+1]=w+1;
	int l=1;
	_rep(i,1,m+1)
	{
		vector<int>v;
		int nowl=a[l],nowr=-1;
		while(l<=n&&a[l]<b[i])
		{
			if(a[l]>nowr)v.pb(a[l]),nowr=a[l]+k-1;
			l++;
		}
		if(v.size())
		{
			if(!deal(v,b[i-1],b[i]))
			{
				cout<<"-1\n";
				return;
			}
		}
	}
	cout<<(int)res.size()<<'\n';
	for(auto i:res)cout<<i<<" ";
	cout<<'\n';
	return ;
}
signed main()
{
	IOS;
	int T=1;
    cin>>T;
	while(T--)
		solve();
	return 0;
}