设有以下定义和程序: #include<iostream.h> classA1 public: void show1() cout<< classA1”<<end1; ; classA2:public A1 public: void show2() cout<< classA2 <<end1; ; class A3:protected A2 public: voidshow3() cout<< class A1”<<end1; ; void main() A1obj1; A2obj2; A3obj3; 则以下不合语法的调用语句是
A.obj1.show1();
B.obj2.show1();
C.obj3.show1();
D.obj2.show2();