Which of the following statement concerning about the probability concepts is TRUE（）

A. A joint probability is the probability that two or more events happen concurrently.

B. Subjective probability is a probability drawing on observation.

C. A random variable is a quantity whose outcomes are certain.

有如下程序: #include using namespace std; class Mountain{ int height; public:Mountain(int h=0):height(h){ } virtual char *GetName()const {return "山";}int GetHeight() const{return height;} }; class Lushan:public Mountain{ public:Lushan(int d):Mountain(d){ } char *GetName()const {return "庐山";} };int main(){ Mountain *p= new Lushan(1000); cout<GetName()<<"海拔"<GetHeight()<<"米"; return 0;}运行这个程序的输出结果是

A．庐山海拔1000米

B．庐山海拔0米

C．山海拔1000米

D．山海拔0米