题目内容：

People from western countries like to show their politeness directly. Therefore, which situation fits western custom?

A. 〔a: I’m going to sign up for the singing competition tomorrow.〕 〔b: Congratulations!〕

B. 〔a: I plan to go on a trip to Paris on vacation.〕 〔b: Have a good journey!〕

C. 〔a: I won the first prize in English speech contest.〕〔b: Good luck!〕