防虫的关键温度是

A．4℃

B．15℃

C．35℃

D．25℃

E．50℃

下列程序的执行结果为________。 #include＜iostream.h＞ class Point { public: Point(double i,double j){x=i;y=j;} double Area( )const{return 0.0;} private: double x,y; }; class Rectangle:public Point { public: Rectangle(double i,double J,double k,double 1); double Area( )const(return w*h;} private: double w,h; }; Rectangle::Rectangle(double i,double j,double k,double 1):Point(i,j) { w=k;h=l; } void fun(Point&s) { cout＜＜s.Area( )＜＜endl; } void main( ) { Rectangle rec(3.0,5.2,15.0,25.0); fun(rec); }