A、By plane. B、By car. C、By train. D、By bus. D注意对话中的转折连词but, but之后的内容才是说话者的主要意思，听到taking a bus便可选择答案D By bus。

W: Hello, John, this is Alice. I’m calling from work. How’s your mother feeling?
M: That was very thoughtful of you. Morn is out of the hospital but she has to stay in bed a few more days.
Q: where is Alice?

M: You’re going to Chicago this weekend, aren’t you?
W: Yes. I thought I’d fly, but I decided that taking a bus would be cheaper than driving or flying．
Q: How will the woman go to Chicago?