#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using LL = long long;
const int N = 1e5 + 10;

vector <int> G[N];
struct PI {
    int ty;
    int x;
    bool operator < (PI &a) {
        return x < a.x;
    }
};

int head[N], tail[N];
void solve()
{
    int tot = 0;
    int n, m, k, w, x;
    cin >> n >> m >> k >> w;
    vector <PI> p;
    for(int i = 1; i <= n; i++) {
        G[i].clear();
        cin >> x;
        p.push_back({1, x});
    }
    for(int i = 1; i <= m; i++) {
        cin >> x;
        p.push_back({2, x});
    }
    sort(p.begin(), p.end());
    int R = p.size();

    if(p[1].ty == 1 && p[1].x == 1);
    else head[++tot] = 1;
    for(int i = 0; i < R; i++) {
        if(p[i].ty == 1) G[tot].push_back(p[i].x);
        else {
            tail[tot] = p[i].x - 1;
            head[++tot] = p[i].x + 1;
        }
    }
    tail[tot] = w;

    vector <int> ans;
    int cnt = 0;
    for(int i = 1; i <= tot; i++) {
        if(!G[i].size()) continue;
        vector <int> tmp;
        int end = 0;
        for(int j = 0; j < G[i].size(); j++) {
            int x = G[i][j];
            if(x > end) cnt++, end = x + k - 1, tmp.push_back(x);
        }
        if(end <= tail[i]) {
            for(auto it: tmp) ans.push_back(it);
        }
        else {
            int up = tail[i];
            for(int j = int(tmp.size() - 1); j >= 0; j--) {
                if(tmp[j] + k - 1 > up) {
                    tmp[j] = up - k + 1;
                    up = tmp[j] - 1;
                }
                else break;
            }
            if(up < head[i]) {
                cout << -1 << '\n';
                return;
            }
            else {
                for(auto it : tmp) {
                    ans.push_back(it);
                }
            }
        }
    }
    cout << ans.size() << '\n';
    for(int i = 0; i < ans.size(); i++) cout << ans[i] << ' ';
    cout << '\n';
}
int main() {
    ios::sync_with_stdio(0); cin.tie(0);
    int t;
    cin >> t;
    while(t--) solve();
    return 0;
}