import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        ArrayList<Integer> answer = new ArrayList<>();
        Scanner sc = new Scanner(System.in);
        int t = sc.nextInt();
        for (int i = 0; i < t; i++){
            int n = sc.nextInt();
            int k = sc.nextInt();
            sc.nextLine();
            int[] data = new int[n];
            for (int j = 0; j < n; j++) {
                data[j] = sc.nextInt();
            }
            Arrays.sort(data);
            int x = 0;
            int left = data[0] - k;
            int right = data[0] + k;
            for (int j = 0; j < n && x < n; j++) {
                if (j == 0) {
                    x += 2 * k + 1;
                } else {
                    int left1 = data[j] - k;
                    int right1 = data[j] + k;
                    if (left1 <= right){
                        x += right1 - right;
                    }else {
                        x += 2 * k + 1;
                    }
                    left = left1;
                    right = right1;
                }
            }
            if (x > n){
                answer.add(n);
            }else {
                answer.add(x);
            }
        }
        for (int j = 0; j < answer.size(); j++){
            System.out.println(answer.get(j));
        }
    }
}