#include<bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;
#define ll long long
#define ull unsigned long long
#define mp make_pair
#define pb push_back
#define se second
#define fi first
#define ret(i,a,b) for(int i = (a);i<=(b);++i)
const int N=2e5+5;
const int M=1e6+5;
const ll inf=1e18;
const ll mod=998244353;
ll ksm(ll a,ll b)
{
	ll ret=1;
	while(b)
	{
		if(b&1) ret=ret*a%mod;
		a=a*a%mod;
		b>>=1;
	}
	return ret;
}
inline int read()
{
    int x=0,f=1;
    char ch=getchar();
    while(ch<'0'||ch>'9')
	{
        if(ch=='-')
            f=-1;
        ch=getchar();
    }
    while(ch>='0'&&ch<='9')
	{
        x=(x<<1)+(x<<3)+(ch^48);
        ch=getchar();
    }
    return x*f;
}
int n,m,k,w,x,ff;
int ans;
vector<int> noww;
vector<int> anss;
void work(int l,int r)
{
	int tot=0,now=0;
	if(ff==0) return ;
	//printf("l=%d,r=%d\n",l,r);
	if(r-l-1<k&&(!noww.empty()))
	{
		ff=0;
		//printf("plf?");
		return ;
	}
	int aa[N];
	for(auto u:noww)
	{
		if(now==0)
		{
			now=u;
			tot=1;
			aa[tot]=now;
		}
		if(u>now+k-1)
		{
			now=u;
			tot++;
			aa[tot]=now;
		}
		//printf("u=%d,now=%d\n",u,now);
	}
	
	if(tot*k>r-l-1)
	{
		ff=0;
		return ;
	}
	//cout<<"?!?\n";
	//ret(i,1,tot) cout<<aa[i]<<" ";
	//cout<<endl;
	for(int i=tot;i;--i)
	{
		if(i==tot)
		{
			if(aa[i]+k-1<r)
			{
				break;
			}
			else 
			{
				aa[i]=r-k;
			}
		}
		else
		{
			if(aa[i]<=aa[i+1]-k) break;
			else
			{
				aa[i]=aa[i+1]-k;
			}
		}
	}
	//printf("??");
	if(aa[1]<=l)
	{
		ff=0;
		//printf("aaplf?\n");
		return ;
	}
	ret(i,1,tot) anss.pb(aa[i]); 
	ans+=tot;
	return ;
}
void solve()
{
	cin>>n>>m>>k>>w;
	map<int,int> M;
	ans=0;
	ff=1;
	anss.clear();
	ret(i,1,n)
	{
		cin>>x;
		M[x]=1;
	}
	ret(i,1,m)
	{
		cin>>x;
		M[x]=2;
	}
	int now=0;

	noww.clear();
	for(auto u:M)
	{
		//printf("?u.fi=%d,u.se=%d\n",u.fi,u.se);
		if(ff==0) break;
		if(u.se==2)
		{
			//printf("?:now=%d,u.fi=%d,u.se=%d\n",now,u.fi,u.se);
			work(now,u.fi);
			noww.clear();
			now=u.fi;
		}
		if(u.se==1) noww.pb(u.fi);
	}
	work(now,w+1);
	if(ff) cout<<ans<<endl;
	  else cout<<"-1\n";
	if(ff)
	{
		for(auto u:anss) cout<<u<<" ";
		cout<<endl;
	}
	return ;
}
int main()
{
	ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
	int _=1;
	cin>>_;
	while(_--) solve();
	return 0;
}