using System;

public class Program

{

    public static void Main()

    {

        Guid? nullGuid = null;

        string tostringValue = nullGuid.ToString();

        string output = tostringValue == null 

            ? "null" 

            : tostringValue == string.Empty 

                ? "empty" 

                : "something else";

        Console.WriteLine(output);

    }

}