Dynamic Binding with datahiding query

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using NUnit.FrameWork;


namespace DynamicBindingWithHiding
{
class A
{
public virtual void Whoareyou()
{
Console.WriteLine("I am in A");
Console.ReadLine();
}

}
class B:A
{
public override void Whoareyou()
{
Console.WriteLine("I am in B");
Console.ReadLine();
}

}
class C : B
{
public new virtual void Whoareyou()
{
Console.WriteLine("I am in C");
Console.ReadLine();
}

}
class D : C
{
public override void Whoareyou()
{
Console.WriteLine("I am in D");
Console.ReadLine();
}

}



class Program
{
static void Main(string[] args)
{
//C c = new D();
//c.Whoareyou();

A a = new D();
a.Whoareyou(); //It shows "I am in B" how?

}
}
}