- We are going on a trip to Mount Huang next month.-.A. CongratulationsB. Good luckC. Enjo

问题补充：

- We are going on a trip to Mount Huang next month.

-.

A. Congratulations

B. Good luck

C. Enjoy yourselves

D. Best wishes

答案：

A. Congratulations

B. Good luck

(答案→)C. Enjoy yourselves

D. Best wishes

解析：句意:-下个月我们打算去黄山旅行。-祝你们玩得开心。Congratulations. 祝贺你；Good luck. 祝你好运；Enjoy yourselves.祝你们玩得开心；Best wishes.给你我最美好的祝福。根据这个对话的情景可知选C。