#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

void solve() {
    int T;
    cin >> T;
    for (int t = 0; t < T; ++t) {
        int n, m, k, w;
        cin >> n >> m >> k >> w;
        vector<int> a(n);
        for (int i = 0; i < n; ++i) cin >> a[i];
        vector<int> b(m);
        for (int i = 0; i < m; ++i) cin >> b[i];
        sort(a.begin(), a.end());
        sort(b.begin(), b.end());
        
        vector<pair<int, int>> allowed_strips;
        int prev = 0;
        for (int i = 0; i < m; ++i) {
            int s = prev + 1;
            int e = b[i] - 1;
            if (s > e) {
                prev = b[i];
                continue;
            }
            int l_start = s;
            int l_end = e - k + 1;
            if (l_end < l_start) {
                prev = b[i];
                continue;
            }
            for (int l = l_start; l <= l_end; ++l) {
                allowed_strips.emplace_back(l, l + k - 1);
            }
            prev = b[i];
        }
        int s = prev + 1;
        int e = w;
        if (s > e) {
            prev = w;
            continue;
        }
        int l_start = s;
        int l_end = e - k + 1;
        if (l_end >= l_start) {
            for (int l = l_start; l <= l_end; ++l) {
                allowed_strips.emplace_back(l, l + k - 1);
            }
        }
        
        sort(allowed_strips.begin(), allowed_strips.end(), [](const pair<int, int>& a, const pair<int, int>& b) {
            return a.second < b.second;
        });
        
        vector<int> selected_strips;
        int j = 0;
        for (auto& strip : allowed_strips) {
            if (j >= n) break;
            if (strip.first <= a[j] && a[j] <= strip.second) {
                selected_strips.push_back(strip.first);
                while (j < n && a[j] <= strip.second) {
                    j++;
                }
            }
        }
        
        if (j == n) {
            cout << selected_strips.size() << endl;
            for (int l : selected_strips) {
                cout << l << " ";
            }
            cout << endl;
        } else {
            cout << -1 << endl;
        }
    }
}

int main() {
    solve();
    return 0;
}