a.A demonstration in our computer programming class will be given by Professor Smith at 1：30 p.m.on Thursday， December 21， in Room 1207 in Classroom Building No.1.b.All other students and teachers of our college are welcome to attend.c.All students and teachers of the Computer Department are expected to be present.Question：What is the correct order of the sentences given above？

A.a-c-b

B.a-b-c

C.c-a-b

D.b-a-c

正确答案：a-c-b