using System;

    public class MyBase

    {

        protected Action Foo()

        {

            return Local;

            void Local()

            {

                Console.WriteLine("Hello world");

            }

        }

    }

    public class MyDerived : MyBase

    {

        public void HelloWorld()

        {

            var f = Foo();

            f();

        }

    }

    public class Program

    {

        public static void Main()

        {

            var o = new MyDerived();

            o.HelloWorld();

        }

    }