#include <bits/stdc++.h>

using namespace std;


using i32 = int32_t;
using i64 = long long;

#define int i64

using vi = vector<int>;
using pii = pair<int,int>;

void solve() {
	int n, m, k, w;
	cin >> n >> m >> k >> w;

	vi r(n);
	for(int i = 0; i < n; i ++) 
		cin >> r[i];
	
	vi b(m);
	for(int i = 0; i < m; i ++) 
		cin >> b[i];

	b.push_back(0), b.push_back(w + 1);
	ranges::sort(r);
	ranges::sort(b);

	auto calc = [k](int n, vi a) -> vi {
		vi l , r , lst;

		for(auto i : a) {
			if(r.empty() or i > r.back()){
				l.push_back(i);
				r.push_back(i + k - 1);
				lst.push_back(i);
			}else{
				lst.back() = i;
			}
		}

		int R = n;
		for(int i = l.size() - 1; i >= 0; i --) {
			if(r[i] <= R) break;
			if(lst[i] > R) return vi();
			r[i] = R;
			l[i] = R - k + 1;
			R = l[i] - 1;
		}
		
		if(l[0] >= 1) return l;
		else return vi();
	};

	vi res, cur;
	for(int i = 0, j = 0; i + 1 < b.size() and j < n; i ++) {
		cur = vi();
		while(j < n and b[i] < r[j] and r[j] < b[i + 1])
			cur.push_back(r[j] - b[i]), j ++;
		if(cur.empty()) continue;


		auto ret = calc(b[i + 1] - b[i] - 1, cur);
		if(ret.empty()) {
			cout << -1 << "\n";
			return;
		}
		for(auto x : ret)
			res.push_back(x + b[i]);
	}

	cout << res.size() << "\n";
	for(auto i : res) assert(1 <= i <= w - k + 1 ), cout << i << " ";
	cout << "\n";
	return;
}

i32 main() {
	ios::sync_with_stdio(false), cin.tie(nullptr);

	int T;
	cin >> T;
	while(T --)
		solve();

	return 0;
}