#include <bits/stdc++.h>
using namespace std;
#define int              long long int
#define double           long double
#define print(a)         for(auto x : a) cout << x << " "; cout << endl


const int M = 1000000007;
const int N = 3e5+9;
const int INF = 2e9+1;
const int LINF = 2000000000000000001;

inline int power(int a, int b, int mod=M) {
    int x = 1;
    a %= mod;
    while (b) {
        if (b & 1) x = (x * a) % mod; 
        a = (a * a) % mod;
        b >>= 1;
    }
    return x;
}


//_ ***************************** START Below *******************************




vector<int> b;

int consistency(int n, int k){

    sort(begin(b), end(b));
    
    n = b.size();
    vector<int> prefix(n+1);
    vector<int> suffix(n+1);


    for(int i=0; i<n; i++){
        prefix[i+1] = prefix[i] + b[i];
    }
    for(int i=n-1; i>=0; i--){
        suffix[i] = suffix[i+1] + b[i];
    }

    int ans = INT32_MAX;
    for(int i=0; i<n; i++){

        int j = i;
        while(j<n && b[j] - b[i] <= k) j++;

        int cost = prefix[i] +  suffix[j] - (n-j)*(b[i]+k);
        ans = min(ans, cost);
    }

    return ans;

}















int practice(int n, int k){


    return 0;
}





void solve() {
    
    int n, k;
    cin>> n >> k;
    
    b.resize(n);
    for(int i=0; i<n; i++) cin >> b[i];
    
    cout << consistency(n, k) << endl;


}





int32_t main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    int t = 1;
    cin >> t;
    while (t--) {
        solve();
    }

    return 0;
}