A、Strangers. B、Friends. C、Relatives. D、Coworkers. A由录音对话可知两人是在旅行当中因为座位问题认识的, 并相互作了自我介绍, 故选A。

W: Excuse me. Is this seat taken?
M: No. it’s not taken.  
W: Oh. thank you.  
M: Oh. let me help you with this.  
W: Oh. thank you.  
M: Do you want to sit by the window?
W: No. no. no. I like the aisle seat better. You can sit by the window.  
M: My name is Mike Gerard Hogan. Pleased to meet you.  
W: I’m Elsa Tobin. How do you do?
M: Do you live in New York?
W: No. no. I’m from Florida.  
M: I am, too. But didn’t you just get on?
W: No, no. I just changed my seat. A man next to me was smoking, and smoke really bothers me.  
What is the most probable relationship between the two speakers?
Why did the woman changed her seat?