using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

}

​

public class CarList 

{ 

   public virtual Car Car() => new Car(); 

} 

public class PickupList : CarList 

{ 

   public override Pickup Car() => new Pickup(); 

} 

public class Car {} 

public class Pickup : Car {}