#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back

void solve() {
    int n, m, k, w;
    cin >> n >> m >> k >> w;
    vector<int>a(n + 1);
    set<int>st;
    for (int i = 1 ; i <= n ; i++)
        cin >> a[i];
    for (int i = 1 ; i <= m ; i++) {
        int x;
        cin >> x;
        st.insert(x);
    }
    st.insert(0);
    st.insert(w + 1);
    sort(a.begin() + 1, a.end());
    vector<int>ans;
    for (int i = 1; i <= n; i++) {
        auto it = st.upper_bound(a[i]);
        int ri = *it, le = *prev(it);
        //cout << ri << ' ' << le << '\n';

        int cur = i;
        vector<int> b;
        while (1) {
            int pos = upper_bound(a.begin() + 1, a.end(), a[cur] + k - 1) - a.begin() - 1;
            //cout << pos << ' ';
            if (a[pos] + k - 1 >= ri) {
                int suf = min(a[cur] , ri - k);
                for (int j = b.size() - 1 ; j >= 0 ; j--) {
                    if (b[j] + k - 1 >= suf) {
                        b[j] = suf - k;
                        suf = b[j];
                    } else {
                        break;
                    }
                }
                if (b.size() > 0 && b[0] <= le) {
                    cout << "-1\n";
                    return;
                }
                if(ri - k <= le){
                	cout << "-1\n";
                	return;
                }
                b.push_back(ri - k);    
            } else {
                b.push_back(a[cur]);
            }
            cur = pos + 1;
            if (cur > n || a[cur] >= ri)
                break;
        }
        for(auto x : b) ans.push_back(x);
        i = cur - 1;
        //cout << '\n';
    }

    cout << ans.size() << '\n';
    for (auto x : ans) {
        cout << x << ' ';
    }
    cout << '\n';
}



signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
    cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}