—Welcome to Haikou. —. A. Thank you very much B. Nice to see you C. Hello

问题补充：

—Welcome to Haikou.

—.

A. Thank you very much B. Nice to see you C. Hello

答案：

解析：句意:--欢迎来到海口。---谢谢。面对对方的欢迎，应说：谢谢。Nice to see you和hello的对话与答语都是一样的。故选A。