下面一段代码，输出结果是什么？   class grandfather:       def speak(self):           print("1")   class father(grandfather):       def speak(self):           print("2")   class son(father):       def speak(self):          print("3")  class son2(grandfather):      def speak(self):          print("4")  class myclass(son, son2):      def speak(self):          print("5")   obj = myclass()  obj.speak() A.

5 B.

4 C.

3 D.

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