单项选择题

下面程序的输出结果是
#include<iostream.h>
class A
public:
A( ) cout < < "construtA" < < endl;
Virtual~A( ) cout < < "destructA" < < endl;;
class B: public A
;
class C:public A
;
class D:public B,public C
;
void main( )
D d;

A.constructA
B.constructA
C.constructA
D.constructA
destructA constructA constructA constructA
destructA constructA constrnctA
destructA destructA constructA
destructA destructA destructA
destrctA destructA
destructA