What will be the output of the following C# code?

{
 delegate string f(string str);
 class sample
 {
     public static string fun(string a)
     {
         return a.Replace('k', 'o');
     }
 }
 class Program
 {
     static void Main(string[] args)
     {
         f str1 = new f(sample.fun);
         string str = str1("Test Ykur C#.NET Skills");
         Console.WriteLine(str);
         Console.ReadLine();
     }
 }
}