—Your father's back home now, _____ he?

—Yes, he _____ been at home for half an hour. [ ]

A. isn't, has

B. hasn't, has

C. hasn't, is

D. isn't, is

依据车辆购置税的有关规定，下列车辆中可以享受减免税的是( )。

A．国家机关购买的小汽车
B．留学人员购买的进口小汽车
C．有突出贡献专家购买的小汽车
D．国际组织驻华机构购买的自用小汽车