A、Three quarters of an hour. B、A quarter of an hour. C、Ten minutes. D、Half an hour. B对话中，女士说现在已经七点半了，他们得抓紧时间赶去火车站。男士说他们只需要半个小时就可

M：Katharine，have you turned the air-conditioning on? The room is so hot.
W：Sorry，sir．It is reported that flu is threatening us right now．As a preventative measure，we are told to let in fresh air by opening the windows and not to use the air conditioners．
Q：What can we learn from the conversation?

W：We’ll have to hurry if we’re going to be on time to get to the railway station．It’s already seven thirty．
M：Well，it takes only half an hour to get to the railway station，and the train doesn’t leave until eight fifteen．I think we’ll make it if we leave immediately．
Q：How much time do they have once they arrive at the railway station?