問題文の記述の通りに条件を満たす携帯電話の機種を列挙すればよいです。

解答例 (C++)

#include <bits/stdc++.h>

int ri() {
	int n;
	scanf("%d", &n);
	return n;
}

int main() {
	int n = ri();
	int m = ri();
	std::vector<std::vector<int> > a(n);
	for (int i = 0; i < n; i++) {
		a[i].resize(ri());
		for (auto &j : a[i]) j = ri();
	}
	int p = ri();
	int q = ri();
	std::vector<int> b(p);
	for (auto &i : b) i = ri();
	
	int res = 0;
	for (auto i : a) {
		int cur = 0;
		for (auto j : i) cur += std::count(b.begin(), b.end(), j);
		res += cur >= q;
	}
	printf("%d\n", res);
	
	return 0;
}