单项选择题

有如下类定义: class B{ private: void fun1(){ } protected: void fun2(){ } public: void fun3(){ } }; class D : public B { protected: void fun4(){ } };若obj是类D的对象,则下列语句中正确的是

A.obj.fun1();
B.obj.fun2();
C.obj.fun4();
D.obj.fun3();