using System;

public delegate Small covarDel(Big mc);

​

public class Program

{

    public static Big Method1(Big bg)

    {

        Console.WriteLine("Method1");

        return new Big();

    }

    public static Small Method2(Big bg)

    {

        Console.WriteLine("Method2");

        return new Small();

    }

    public static void Main(string[] args)

    {

        covarDel del = Method1;

​

        Small sm1 = del(new Big());

​

        del= Method2;

        Small sm2 = del(new Big());

    }

}

​

public class Small

{ 

​

}

public class Big: Small

{

​

}

public class Bigger : Big

{ 

}