import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

public class Main {
    public static long n, m, temp;
    public static ArrayList<Long> list = new ArrayList<Long>();//存放输入的数
    public static ArrayList<Long> result = new ArrayList<Long>();
    
    public void getResult() {
        Collections.sort(list);
        for(int i = 0, j = list.size() - 1;m > 0;) {
            if(m >= 2) {
                long a1 = list.get(i) * list.get(i + 1);
                long a2 = list.get(j) * list.get(j - 1);
                if(a2 > a1) {
                    temp *= list.get(j);
                    j--;
                    m--;
                } else {
                    temp *= a1;
                    i = i + 2;
                    m = m - 2;
                }    
            } else {
                if(m == 1) {
                    temp *= list.get(j);
                    j--;
                    m--;
                }
            }
        }
        result.add(temp);
    }
    
    public static void main(String[] args) {
        Main test = new Main();
        Scanner in = new Scanner(System.in);
        int t = in.nextInt();
        while(t > 0) {
            t--;
            n = in.nextLong();
            m = in.nextLong();
            temp = 1;
            list.clear();
            for(int i = 0;i < n;i++) {
                long a = in.nextLong();
                list.add(a);
            }
            test.getResult();
        }
        for(int i = 0;i < result.size();i++)
            System.out.println(result.get(i));
    }
}