已定义一个圆的类Circle: class Circle{private: double r;public:void SetR(double x) { r = x; }double GetArea( ) { return 3.14*r*r; }}; 下列语句中正确的是( )。
A、Circle c; c.r = 10.5; cout
B、Circle c; c.SetR(10.5); cout
C、Circle c; cout
D、Circle c; SetR(10.5); cout