#include <bits/stdc++.h>
#define pb emplace_back
#define fst first
#define scd second
#define mkp make_pair
#define uint unsigned
#define mems(a, x) memset((a), (x), sizeof(a))

using namespace std;
typedef long long ll;
typedef double db;
typedef unsigned long long ull;
typedef long double ldb;
typedef pair<ll, ll> pii;

const int maxn = 1000100;

ll n, m, K, W, a[maxn], b[maxn], lsh[maxn], tot, c[maxn], d[maxn], f[maxn], g[maxn];

namespace SGT {
	pii a[maxn << 2];
	
	inline void pushup(int x) {
		a[x] = min(a[x << 1], a[x << 1 | 1]);
	}
	
	void build(int rt, int l, int r) {
		if (l == r) {
			a[rt] = mkp(1e18, l);
			return;
		}
		int mid = (l + r) >> 1;
		build(rt << 1, l, mid);
		build(rt << 1 | 1, mid + 1, r);
		pushup(rt);
	}
	
	void update(int rt, int l, int r, int x, ll y) {
		if (l == r) {
			a[rt].fst = y;
			return;
		}
		int mid = (l + r) >> 1;
		(x <= mid) ? update(rt << 1, l, mid, x, y) : update(rt << 1 | 1, mid + 1, r, x, y);
		pushup(rt);
	}
	
	pii query(int rt, int l, int r, int ql, int qr) {
		if (ql <= l && r <= qr) {
			return a[rt];
		}
		int mid = (l + r) >> 1;
		pii res(1e18, 0);
		if (ql <= mid) {
			res = min(res, query(rt << 1, l, mid, ql, qr));
		}
		if (qr > mid) {
			res = min(res, query(rt << 1 | 1, mid + 1, r, ql, qr));
		}
		return res;
	}
}

void solve() {
	scanf("%lld%lld%lld%lld", &n, &m, &K, &W);
	for (int i = 1; i <= n; ++i) {
		scanf("%lld", &a[i]);
	}
	for (int i = 1; i <= m; ++i) {
		scanf("%lld", &b[i]);
	}
	tot = 0;
	lsh[++tot] = 0;
	lsh[++tot] = W;
	for (int i = 1; i <= n; ++i) {
		if (a[i] + K <= W) {
			lsh[++tot] = a[i] + K;
		}
		if (a[i] + K - 1 <= W) {
			lsh[++tot] = a[i] + K - 1;
		}
		lsh[++tot] = a[i];
		if (a[i] - K >= 1) {
			lsh[++tot] = a[i] - K;
		}
	}
	for (int i = 1; i <= m; ++i) {
		if (b[i] + K <= W) {
			lsh[++tot] = b[i] + K;
		}
		lsh[++tot] = b[i];
		lsh[++tot] = b[i] - 1;
		if (b[i] - K >= 1) {
			lsh[++tot] = b[i] - K;
		}
	}
	sort(lsh + 1, lsh + tot + 1);
	tot = unique(lsh + 1, lsh + tot + 1) - lsh - 1;
	for (int i = 1; i <= tot; ++i) {
		c[i] = d[i] = 0;
	}
	for (int i = 1; i <= n; ++i) {
		a[i] = lower_bound(lsh + 1, lsh + tot + 1, a[i]) - lsh;
		++c[a[i]];
	}
	for (int i = 1; i <= m; ++i) {
		b[i] = lower_bound(lsh + 1, lsh + tot + 1, b[i]) - lsh;
		++d[b[i]];
	}
	for (int i = 1; i <= tot; ++i) {
		c[i] += c[i - 1];
		d[i] += d[i - 1];
	}
	SGT::build(1, 1, tot);
	f[1] = 0;
	SGT::update(1, 1, tot, 1, 0);
	ll ans = 1e18, k = -1;
	for (int i = 2; i <= tot; ++i) {
		if (lsh[i] < K) {
			continue;
		}
		int p = upper_bound(lsh + 1, lsh + tot + 1, lsh[i] - K) - lsh - 1;
		if (d[i] > d[p]) {
			continue;
		}
		int l = 1, r = p, q = -1;
		while (l <= r) {
			int mid = (l + r) >> 1;
			if (c[p] == c[mid]) {
				q = mid;
				r = mid - 1;
			} else {
				l = mid + 1;
			}
		}
		pii t = SGT::query(1, 1, tot, q, p);
		f[i] = t.fst + 1;
		g[i] = t.scd;
		SGT::update(1, 1, tot, i, f[i]);
		if (c[i] == c[tot]) {
			if (f[i] < ans) {
				ans = f[i];
				k = i;
			}
		}
	}
	if (ans > 1e17) {
		puts("-1");
		return;
	}
	printf("%lld\n", ans);
	while (k > 1) {
		printf("%lld ", lsh[k] - K + 1);
		k = g[k];
	}
	putchar('\n');
}

int main() {
	int T = 1;
	scanf("%d", &T);
	while (T--) {
		solve();
	}
	return 0;
}