·         阅读下面代码，输出结果是什么？   class grandfather:      def speak(self):           print("xiaobai")    class father(grandfather):       pass   class son(father):       pass    class son2(grandfather):       pass   class myclass(son, son2):      pass  obj = myclass()  obj.speak() A.

 son B.

 xiaobai C.

 son2 D.

myclass