A、6: 10. B、6: 55. C、5: 35. D、5: 45. C本题的问题关键词是what time。对话中提到飞机将在6：15离开，现在只剩下40分钟，所以可以推出现在是5：35，因此选C。

W: Go to bed early and get some rest, Jack.
M: But I have to study. We’ re going to have a history test tomorrow morning.
Q: What is Jack?

W: The plane leaves at 6: 15. Do we have time to eat first?
M: No. We have only got 40 minutes until departure time.
Q: What time is it now?