#include<bits/stdc++.h>
using namespace std;
const int N=1e5+5;
int n,m,k,w;
int a[N],b[N];
int cur;
vector<int>res;
bool solve(int l,int r)
{
    if(l>r)return true;
    vector<int>v;
    while(cur<=n&&a[cur]>=l&&a[cur]<=r)
    {
        v.push_back(a[cur]);
        cur++;
    }
    if(v.empty())return true;
    int x=v.front(),y=v.back();
    int len=y-x+1;
    int cnt=(len-1)/k+1;
    if(l+cnt*k-1>=y&&l+cnt*k-1<=r)
    {
        for(int i=0;i<cnt;i++)
        {
            res.push_back(l);
            l+=k;
        }
        return true;
    }
    if(r-cnt*k+1<=x&&r-cnt*k+1>=l)
    {
        for(int i=0;i<cnt;i++)
        {
            res.push_back(r-k+1);
            r-=k;
        }
        return true;
    }
    if(x+cnt*k-1<=r)
    {
        for(int i=0;i<cnt;i++)
        {
            res.push_back(x);
            x+=k;
        }
        return true;
    }
    if(y-cnt*k+1>=l)
    {
        for(int i=0;i<cnt;i++)
        {
            res.push_back(y-k+1);
            y-=k;
        }
        return true;
    }
    return false;
}
bool work()
{
    sort(a+1,a+n+1);
    sort(b+1,b+m+1);
    res.clear();
    cur=1;
    if(!solve(1,b[1]-1))return false;
    for(int i=1;i<m;i++)
        if(!solve(b[i]+1,b[i+1]-1))return false;
    if(!solve(b[m]+1,w))return false;
    return true;
}
int main()
{
    int t;
    cin>>t;
    while(t--)
    {
        cin>>n>>m>>k>>w;
        for(int i=1;i<=n;i++)
            cin>>a[i];
        for(int i=1;i<=m;i++)
            cin>>b[i];
        if(!work())cout<<-1<<endl;
        else
        {
            cout<<res.size()<<endl;
            for(auto &x:res)
                cout<<x<<" ";
            cout<<endl;
        }
    }
    return 0;
}