有如下类定义和变量定义: class Parents{ public: int publicData; private: int privateData; }; class ChildA : public Parents{ *类体略* }; class ChildB : private Parents{ *类体略* }; ChildA a; ChildB b;下列语句中正确的是
                                                            
                                                                A.cout<< a.publicData <B.cout<< a.privateData <C.cout<< b.privateData <D.cout<< b.publicData <