using System;

public class Program

{

    public static void Main()

    {

        var a = new A();

        Console.WriteLine(a.a);

        a.PrintA();

        var b  = new B();

        b.PrintA();

    }

}

​

public class A {

    protected internal int a = 10 ; 

    public void PrintA(){

        Console.WriteLine(a);   

    }

}

​

​

public class B : A {

    public new void PrintA(){

        Console.WriteLine(a);   

    }

}