单项选择题

Questions 11 to 18 are based on the conversation you have just heard.

A.From 8 a.m. to 5 p.m.
B.From 8 a.m. to 6 p.m.
C.From 9 a.m. to 5 p.m.
D.From 9 a.m. to 6 p.m.