Does Liu Hui serve in the army?No,but he ___in the army for three years.A.servedB.has servedC.is servingD.would serve选哪个,为什么?

Does Liu Hui serve in the army?No,but he ___in the army for three years.
A.servedB.has servedC.is servingD.would serve选哪个,为什么?

B
现在完成时,表示对现在的影响,指现在不用服兵役了

b for _+时间段 用现在完成时

选择C呀