using System;

​

public class classA

{

    public virtual void Display()

    {

        Console.WriteLine("Class A called");

    }

}

​

public class classB :classA

{

  public new void Display()

  {

  Console.WriteLine("Class B called");

  }

}

public class Program

{

    public static void Main()

    {

        classB c1 = new classB();

        c1.Display();

        classA c2 = new classA();

        c2.Display();

        classA c3 = new classB();

        c3.Display();

    }

}