A、4:30 B、4:00 C、5:00 D、5:30 A女士提到了两个时间点：4：30和5：30，但问题是“Bob什么时候离开?”故应该选A。

M: Good morning, Jane. How are you?
W: Oh, fine. I don’ t have to work today and come here for lunch.
Q: Where did the talk probably take place?

M: When do you think Bob will be back?
W: When he left at 4: 30, he said that he would be back at 5: 30.
Q: When did Bob leave?