#include<bits/stdc++.h>
using namespace std;
#define nl "\n"
#define fi first
#define se second
#define pb push_back
#define ll long long
#define ull unsigned ll
#define RV  return void
#define inf 2000000000
#define sz(x) int(x.size())
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define Mini(x) *min_element(all(x))
#define Maxi(x) *max_element(all(x))
#define fixed(n) fixed << setprecision(n)
#define ceil(w, m) (((w) / (m)) + ((w) % (m) ? 1 : 0))
#define cin(v) for (auto&i:v) cin >> i;
#define cout(v) for (auto&i:v) cout << i << " ";
#define clr(memo, x) memset(memo, x, sizeof memo)
#define updmin(a, b) a = min(a, b)
#define updmax(a, b) a = max(a, b)
#define vi vector < int >
#define vl vector < ll >
#define vc vector < char >
#define vs vector < string >
#define v2i vector < vector < int > >
#define v2l vector < vector < int > >
#define seti set < int >
#define setl set < ll >
#define mapii map < int , int >
#define mapll map < ll , ll >
#define mapli map < ll , int >
#define mapci map < char , int >
#define mapsi map < string , int >
#define pll pair < ll , ll >
#define pii pair < int , int >
#define range(l,r,x) for(int i=l ; i < r ; i+=x)
#define FastCode ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
vector < string > ternary= {"NO\n" , "YES\n"};

void  Zainab(){
            #ifndef ONLINE_JUDGE
              freopen("input.txt", "r", stdin);
              freopen("output.txt", "w", stdout);
            #endif
}


/*================================  Prblem solution  ================================ */


void myCode(){

int n, m ;
cin >> n >> m ;
vector<ll > v(n), pref(n+1);
for(auto& i : v) cin >> i;

sort( v.begin() , v.end());

ll ans =0;
for(int i = 1 ; i < n ; i++){
    pref[i]= pref[i-1]+ v[i]-v[i-1];
}

// cout(pref);
// cout << nl ;

for(int i =1 ; i < n ; i++){
    pref[i]= (((v[i]-v[i-1]) * i ) % m   + pref[i-1] ) % m  ;
    ans +=pref[i] ;
    ans %= m;
}

cout << ans << nl;



}




int main(){
                                   FastCode ;
                              //      Zainab() ;

    int testCase=1;
          cin >> testCase ;
      for(int i=1 ; i<= testCase ; i++)
        myCode();

    return 0;
}