以下程序运行后的输出结果是
#define F(X，Y)(X) * (Y)
main( )
int a=3，b=4；
printf("%d\n"，F(a++，b++))；

A．12

B．15

C．16

D．20

An airline passenger is planning a trip that involves three connecting flights that leave from Airports A, B, and C, respectively. The first flight leaves Airport A every hour，beginning at 8:00 a.m., and arrives at Airport B   hours later. The second flight leaves Airport B every 20 minutes, beginning at 8:00 a.m., and arrives at Airport C hours later. The third flight leaves Airport C every hour, beginning at 8.45 a.m. What is the least total amount of time the passenger must spend between flights if all flights keep to their schedules ？（）

A.25 min

B.1 hr 5 min

C.1 hr 15 min

D.2 hr 20 min

E.3 hr 40 min