单项选择题

有如下类定义: class Point{ public: Point(int xx=0,int yy=0):x(xx),y(yy) { } private: int x,y; }; class Circle:public Point{ public: Circle(int r):radius(r) { } private: int radius; };派生类Circle中数据成员的个数为

A.1
B.2
C.3
D.5