Task: Dialogue Generation
Input (English): F: What are the pupils doing there? They're picking up the plastic bags on the street, but the plastic bags are so dirty. ,M: They are doing that to remind people to protect the environment. You know, the white pollution is so serious these years.
(A) F: Wow, that's meaningful! It is good to remind people about enviroment by doing  so. (B) F: Yes, especially the plastic bottles. It's good for pupils to pick them up to remind people to save money. (C) F: Sounds good. It is good to pick up those clean plastic bags to reuse. (D) F: Excuse me, could you repeat the question?
Output (English): A