#include <cstdio>
#include <algorithm>
#include <cassert>
#include <vector>

const int N = 100005;
int n, m, k, w, a[N], b[N], lr[N], rr[N];
std::vector<int> ans;

bool solve(int l, int r, int lb, int rb) {
	int wall_l = lb, wall_r = lb;
	for (int i = l; i < r; ++i) {
		if (i != l && wall_r >= a[i]) {
			wall_l = std::max(wall_l, a[i]);
			lr[i] = rr[i] = -1;
		} else {
			lr[i] = std::max(a[i] - k + 1, wall_l + 1);
			if (lr[i] > a[i]) return false;
			rr[i] = std::min(a[i], rb - k);
			if (lr[i] > rr[i]) return false;
			wall_l = lr[i] + k - 1;
			wall_r = rr[i] + k - 1;
		}
		//printf("for %d : %d %d\n", i, lr[i] + 1, rr[i] + 1);
	}
	int rwall = rb;
	for (int i = r - 1; i >= l; --i) if (lr[i] != -1) {
		int p = std::min(rwall - k, rr[i]);
		//printf("rwall is %d\n", rwall + 1);
		//printf("put %d on %d\n", i, p + 1);
		assert(p >= lr[i]);
		rwall = p;
		ans.push_back(p);
	}
	return 1;
}

void presolve() {
	scanf("%d%d%d%d", &n, &m, &k, &w);
	for (int i = 0; i < n; ++i) {
		scanf("%d", a + i);
		--a[i];
	}
	for (int i = 0; i < m; ++i) {
		scanf("%d", b + i);
		--b[i];
	}
	b[m++] = -1;
	b[m++] = w;
	std::sort(a, a + n);
	std::sort(b, b + m);
	ans.clear();
	for (int i = 0, j = 0; i < m; ++i) {
		int jj = j;
		while (j < n && a[j] < b[i + 1]) ++j;
		if (jj < j && !solve(jj, j, b[i], b[i + 1])) {
			printf("-1\n");
			return;
		}
	}
	printf("%d\n", (int)ans.size());
	for (int i = 0; i < (int)ans.size(); ++i) printf("%d ", ans[i] + 1);
	printf("\n");
}

int main() {
	int tt;
	scanf("%d", &tt);
	while (tt--) {
		presolve();
	}
	return 0;
}