var result = count1.Union(count2);

using System;
using System. Collections;
using System.Collections.Generic;
using System. Linq;
using System. Text;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Programme2
    {
        static void Main(string[] args)
        {
//create array count1 and count2 of type string
            string[] count1 = { "India", "USA", "UK", "Australia" };
            string[] count2 = { "India", "Canada", "UK", "China" };
//count1.Union(count2) is used to find out the unique element from both the collection
            var result = count1.Union(count2);
//foreach loop is used to print the output conaining in the result
            foreach (var item in result)
            {
                Console.WriteLine(item);
            }
                Console.ReadLine();
        }
    }
}