程序阅读#includeusing namespace std;const float PI=3.14;class shape {public:shape() {}virtual float get_area(){return PI;}};class rectangle:public shape {public:rectangle(float x,float y){a=x;b=y;}float get_area();private:float a, b;};float rectangle::get_area() {return a*b;}class circle : public shape {public:circle(float x) {r=x;}float get_area();private:float r;};float circle::get_area() {return (PI*r*r);}int main() {rectangle r(3,4);circle c(2);shape *p[2]={&r,&c};for(int i=0;i<2;i++)cout<get_area()<

A. 3.143.14
B. 1212
C. 1212.56
D. 12.5612.56