Directly he arrived the bus station, then ____ he had intended to take.

A．a bus did come

B．a bus came

C．came a bus

D．did a bus come

有以下程序：
#include＜iostream＞
using namespace std;
class R

public:
R(int r1,int r2)

R1=r1;
R2=r2;

void print();
void print()const;
private:
int R1,R2;
;
void R::print()

cout＜＜R1＜＜","＜＜R2＜＜end1;

void R::print()const

cout＜＜R1＜＜","＜＜R2＜＜end1;

int main()

R a(5,4);
const R b(20,52);
b.print();
return 0;

执行后的输出结果是( )。

A．5，4

B．4，5

C．20，52

D．52，20