public class Program
    {
        static void Main(string[] args)
        {
            A a = new A();
            a.Test();
            B b = new B();
            b.Test();
            A c = new B();
            c.Test();
            A d = new C();
            d.Test();
            Console.ReadLine();
        }
    }
    public class A
    {

        public virtual void Test()
        {
            Console.WriteLine("A Test()");

        }

    }
    public class B : A
    {
        private new void Test()
        {
            Console.WriteLine("b Test()");

        }
    }
    public class C : B
    {

        public override void Test()
        {
            Console.WriteLine("C Test()");
        }
    }