#include<bits/stdc++.h>
#define int long long
#define ll long long
#define ull unsigned long long
#define db double
#define P point
#define Fr(i,a,b) for(int i=a;i<=b;i++)
#define Fr_(i,a) for(auto i:a)
#define pb push_back
#define fastio ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define pii pair<int,int> 
#define fir first
#define sec second
#define pq priority_queue
#define mkp make_pair
#define memset(a,b) memset(a,b,sizeof(a))
#define new_opt friend bool operator
#define endl '\n'
#define ok cout<<"ok"<<endl

using namespace std;

const int N=2e6+10;
const int N_=1e3+10;
const int M=998244353;
const int inf=2e9;

int n,m,k,w;

vector<int> check(int l,int r,vector<int> v)
{
    //cout<<"l and r : "<<l<<' '<<r<<endl;
    //Fr_(i,v) cout<<i<<' ';cout<<endl;
    vector<int> ans;
    deque<pii> q;
    ans.clear(),q.clear();
    Fr_(i,v)
    {
        //if(!q.empty()) cout<<"q.back(): "<<q.back().sec<<endl;
        if(!q.empty()&&i<=q.back().sec) continue;
        int it=lower_bound(v.begin(),v.end(),i+k-1)-v.begin();
        while(v[it]>i+k-1) it--;
        //cout<<"v[it]:"<<i<<' '<<v[it]<<endl;
        if(q.empty())
        {
            int tmp=max(v[it],l+k-1);
            q.pb({tmp-k+1,tmp});
        }
        else{
            int len=k;
            while(!q.empty()&&q.back().sec+len>=v[it])
            {
                pii tmp=q.back();
                q.pop_back();
                len+=tmp.sec-tmp.fir+1;
            }
            if(q.empty())
            {
                int tmp=max(l+len-1,v[it]);
                q.pb({tmp-len+1,tmp});
            }
            else{
                q.pb({v[it]-len+1,v[it]});
            }
        }
    }
    //cout<<l<<' '<<r<<endl;
    //cout<<q.back().sec<<endl;
    if(q.back().sec>r) return ans;
    else
    {
        while(!q.empty())
        {
            pii tmp=q.front();
            q.pop_front();
            while(tmp.fir<=tmp.sec)
            {
                ans.pb(tmp.fir);
                tmp.fir+=k;
            }
        }
        //cout<<"ans: ";
        //Fr_(i,ans) cout<<i<<' ';cout<<endl;
        return ans;
    }
}
/*
1
6 6 13 78
55 76 53 32 54 58
62 45 21 4 7 61

3
3 8 2 53
32 3 33
35 19 38 20 1 30 10 6
7 10 1 42
3 14 4 36 28 40 22
17 20 12 41 27 7 1 19 13 9
6 6 13 78
55 76 53 32 54 58
62 45 21 4 7 61
*/

void slv()
{
    cin>>n>>m>>k>>w;
    vector<pii> v;
    v.clear();
    Fr(i,1,n)
    {
        int x;
        cin>>x;
        v.pb({x,0});
    }
    Fr(i,1,m)
    {
        int x;
        cin>>x;
        v.pb({x,1});
    }
    sort(v.begin(),v.end());
    v.pb({w+1,1});
    int l=1;
    vector<int> t;
    vector<int> ans;
    t.clear(),ans.clear();
    Fr_(i,v)
    {
        if(i.sec==0)
        {
            t.pb(i.fir);
        }
        else{
            if(t.size()==0) 
            {
                l=i.fir+1;
                t.clear();
            }
            else{
                vector<int> tmp=check(l,i.fir-1,t);
                t.clear();
                l=i.fir+1;
                if(tmp.size()==0)
                {
                    cout<<-1<<endl;
                    return ;
                }
                else{
                    Fr_(j,tmp) ans.pb(j);
                }
            }
        }
    }
    cout<<ans.size()<<endl;
    Fr_(i,ans) cout<<i<<' ';
    cout<<endl;
    ans.clear();
}

signed main()
{
    //fastio;
    int o=1;
    cin>>o;
    while(o--) slv();
}