Helen ________watch TV at home _______ hang out with her friends.

A．would rather, than

B．would, instead of

C．would rather, to

D．would, instead

下列程序的运行结果是______。
#include＜stdio.h＞
main()
int a,b,c,n;
a=2;b=0;c=1;n=1;
while(n＜=3)
c=c*a;b=b+c;++n;
printf("b=%d",b);