下面程序运行的结果是 public abstract class A { public A() { Console.WriteLine('A'); } public virtual void Fun() { Console.WriteLine("A.Fun()"); } } public class B : A { public B() { Console.WriteLine('B'); } public new void Fun() { Console.WriteLine("B.Fun()"); } } static void Main(string[] args) { B b = new B(); b.Fun(); } A. A.Fun() B. B.Fun() C. A B A.Fun() D. A B B.Fun()