录音问的是女士将租车多少天。 对话中女士说只租3天， 因此选B。

【录音原文】
M: Good morning, ABC Car Rental, how can I help you?
W: Good morning, I‟d like to rent a car, please.
M: Sure, is it just for yourself?
W: No, my husband and two children.
M: And (6) how long would you like to rent the vehicle?
W: (6) Just three days, from tomorrow morning.
M: OK, we have a Toyota and a Ford. Which one do you prefer?
W: (7) Which one is less expensive?
M: (7) The Toyota, it is 45 dollars a day.
W: (7) OK, I‟ll take the Toyota.
Q6: How many days will the woman rent the car?
Q7: Why does the woman decide to rent a Toyota?

【解析】录音问的是为什么女士决定租一辆丰田汽车。 对话中女士问哪种车更便宜， 男士说丰田， 女士说她就租丰田。 由此可知女士因为丰田的租金率较低所以租丰田。 故选B。