#include <algorithm>
#include <iostream>
#include <assert.h>
 
using namespace std;
 
int tn, n, k, ai;
 
int main (int argc, char * const argv[]) {
	ios_base::sync_with_stdio(false);
	cin >> tn;
	assert(1 <= tn && tn <= 10);
	while (tn--) {
		long long ret = 0;
		cin >> n >> k;		
		assert(1 <= n && n <= 100000);
		assert(1 <= k && k <= 1000000000);
		for(int i = 0; i < n; i++) {
			cin >> ai;
			assert(1 <= ai && ai <= 1000000000);
			if (ai < k)
				ret += k - ai % k;
			else
				ret += min(ai % k, k - ai % k);
		}
		cout << ret << endl;
	}
    return 0;
}
 
/*
 10 8
 2 9 10 8 2 9 8 6 7 10
 
2 -> 8 : +6
9 -> 8 : +1
10 -> 8 : +2
8 -> 8 : +0
2 -> 8 : +6
9 -> 8 : +1
8 -> 8 : +0
6 -> 8 : +2
7 -> 8 : +1
10 -> 8 : +2
6+1+2+0+6+1+0+2+1+2
*/