#include <iostream>
#include <algorithm>
using namespace std;
typedef long long ll;
const int MOD = 998244353;
const int MAXN = 100005;
ll ksm(ll a,ll b)
{
    ll t = 1;
    while(b){
        if(b&1)    t = t*a%MOD;
        a = a*a%MOD;
        b >>= 1;
    }
    return t%MOD;
}
int a[MAXN];
/*
1
4 1
1 2 3

*/
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        int n,k;
        scanf("%d %d",&n,&k);
        for(int i = 1;i <= n;i++)
        scanf("%d",&a[i]);
        
        sort(a + 1,a + n + 1);
        ll le = a[1] - k,ri = a[1] + k;
        ll ans = ri - le + 1;
        for(int i = 2;i <= n;i++)
        {
            ll nowle = a[i] - k;
            ll nowri = a[i] + k;
            if(nowle > ri)
            ans += nowri - nowle + 1,ri = nowri;
            else if(nowri <= ri)    continue;
            else
            {
                ans += nowri - ri;
                ri = nowri;
            }
        }
        printf("%lld\n",min(ans,1ll*n));
    }
    return 0;
}