单项选择题

有如下程序: #include <iostream> using namespaee std; class Point{ public: static int number; Point( ){number++;} ~Point( ){number--;} }; int Point::number=0; void main( ){ Point*ptr; Point A,B; Point*ptr_point=new Point[3]; ptr=ptr_point; Point C; cout<<Point::number<<endl; delete[ ]ptr; } 程序的输出结果是

A.3
B.4
C.6
D.7