— Mum, I don't like drinking milk. 

— For your health, dear, you ______. [ ]

A. must

B. have to

C. need

D. could

张某在火车站候车室窃得某人一提包，到僻静处打开一看，里面没有钱财，却有手枪一支，子弹若干发，张某便将枪支．子弹放回包内，然后藏于家中。张某的行为构成何罪？

A．非法持有枪支、弹药罪

B．盗窃枪支、弹药罪

C．非法储存枪支、弹药罪

D．非法携带枪支、弹药罪