单项选择题

下面程序的运行结果为
#include<iostream. h>
class A

public:
A( ) cout < <"1";
~A( ) cout < <"2";
;
class B:public A

public:
B( ) cout < <"3";
~B( ) cout < <"4";
;
void main( )

B b;

A) 1234 B) 1324 C) 1342 D) 3142