#include <bits/stdc++.h>
#define int long long
using namespace std;
struct node{
    int pos;
    bool type;
    bool operator < (const node it) const {
        return pos < it.pos;
    }
};

void solve(){
    int n = 0,m = 0,k = 0,w = 0;
    cin >> n >> m >> k >> w;
    vector<node>a(n + m);
    for(int i = 0;i < n;i++){
        cin >> a[i].pos;
        a[i].type = true;
    }
    for(int i = n;i < n + m;i++){
        cin >> a[i].pos;
        a[i].type = false;
    }
    a.push_back({w,false});
    sort(a.begin(),a.end());
    vector<int>ans;
    deque<int>dq;
    int l = 1;
    for(int i = 0;i <= n + m;i++){
        if(a[i].type){
            dq.push_back(i);
        }
        else{
            while(!dq.empty()){
                if(ans.empty() || ans.back() + k - 1 < a[dq.front()].pos){
                    ans.push_back(a[dq.front()].pos);
                }
                dq.pop_front();
            }
            if(i == n + m){
                continue;
            }
            ans.push_back(a[i].pos);
            for(int j = ans.size() - 2;ans[j] >= l && j >= 0;j--){
                if(ans[j] + k > ans[j + 1]){
                    ans[j] = ans[j + 1] - k;
                    if(ans[j] < l){
                        cout << -1 << endl;
                        return;
                    }
                }
            }
            ans.pop_back();
            l = a[i].pos + 1;
        }
    }
    cout << (int)ans.size() << endl;
    for(int x : ans){
        cout << x << ' ';
    }
    cout << endl;
}

signed main(){
    ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
    int t = 0;
    cin >> t;
    while(t--){
        solve();
    }
    return 0;
}