#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
#include <functional>
#include <cassert>

bool solve(int L, const std::vector<int> &a, int R, int w, std::function<void(int)> callback) {
    int n = a.size();
    // std::cerr << "debug(" << L << ", " << R << "): ";
    // for(int i = 0; i < n; ++i) std::cerr << a[i] << char(i == n - 1 ? 10 : 32);
    int p = std::max(a[0] - w + 1, L + 1), l = a[0];
    for(int i = 1; i < n; ++i) {
        if(a[i] <= p + w - 1) continue;
        if(a[i] <= l + w - 1) {
            p = a[i] - w + 1;
            continue;
        }
        callback(p);
        p = std::max(a[i] - w + 1, p + w);
        if(p + w - 1 >= R) return false;
    }
    callback(p);
    return true;
}

void work() {
    int n, m, k, w;
    std::cin >> n >> m >> k >> w;
    std::vector<std::pair<int, int>> c(n + m + 2);
    for(int i = 0; i < n; ++i) std::cin >> c[i].first, c[i].second = 1;
    for(int i = n; i < n + m; ++i) std::cin >> c[i].first, c[i].second = 0;
    c[n + m] = {w + 1, 0};
    c[n + m + 1] = {0, 0};
    std::sort(c.begin(), c.end());

    int ans = 0, l = 0;
    std::vector<int> strip;
    while(l < c.size()) {
        int pre_l = l; l++;
        while(l < c.size() && c[l].second) l++;
        if(l == c.size()) break;
        assert(!c[pre_l].second && !c[l].second);
        int pre = c[pre_l].first;
        if(pre_l == l - 1) continue;
        if(c[l].first - c[pre_l].first - 1 < k) {
            std::cout << "-1\n";
            return ;
        }
        std::vector<int> a(l - pre_l - 1);
        for(int i = pre_l + 1; i < l; ++i) a[i - pre_l - 1] = c[i].first;
        bool flag = solve(c[pre_l].first, a, c[l].first, k, [&](int pos) {
            ans++;
            strip.push_back(std::min(pos, c[l].first - k));
        });
        if(!flag) return std::cout << "-1\n", void(0);
        pre = c[l].first;
    }
    std::cout << ans << char(10);
    for(int i = 0; i < strip.size(); ++i) std::cout << strip[i] << char(i == strip.size() - 1 ? 10 : 32);
    return ;
}

int main() {
    std::ios::sync_with_stdio(false);
    int T; std::cin >> T; while(T--) work();
    return 0;
}