using System;

using System.Collections.Generic;   

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        // Define all of the words to be checked

        var words = new List<string>(){ "Roger", "ROGER", "Test", "Test ", "Dr. Kale", "Dr. Kale" };

        // Get only the distinct words, ignoring case and leading/trailing whitespace

        words = words.Select(w => w.Trim())

                     .Distinct(StringComparer.OrdinalIgnoreCase).ToList();

        // Output each remaining word

        Console.WriteLine(String.Join(",",words.ToArray()));

    }

}