drivers --- wear the safety belt when driving this is the traffic rulea\ canb\ mayc\ willd\ must说理由!

drivers --- wear the safety belt when driving this is the traffic rulea\ canb\ mayc\ willd\ must说理由!
drivers --- wear the safety belt when driving this is the traffic rule
a\ can
b\ may
c\ will
d\ must
说理由!

drivers --- wear the safety belt when driving this is the traffic rulea\ canb\ mayc\ willd\ must说理由!
正确的答案是 d\ must
must 必须
must wear the safety belt 必须系上安全带

选D D项表示必须之意