using System;

using System.Collections.Generic;

using System.Linq;                  

​

public class Program

{

    public static void Main()

    {

        string[] letters = { "A", "B", "C" };

        IEnumerable<string> combined = letters.Select((letter, index) => letter + index);

        foreach (var c in combined)

        {

            Console.WriteLine(c);

        }

    }

}