单选题 Ms. Lee is going to the ______ office to pick up a registered letter.
A. mail
B. package
C. post
D. stamp

【正确答案】 C
【答案解析】Letters(信件)只能去post office(邮局)(C)取。选项(A)mail、选项(B)package和选项(D)stamp均不与office搭配。