Teacher:In this task, you will be presented with a question having multiple possible answers in Vietnamese language. And you should choose a most suitable option out of "A", "B", "C", "D", and "E" based on your commonsense knowledge.
Teacher: Now, understand the problem? Solve this instance: Question: Lợi ích tâm lý của việc vui vẻ là gì? 
 Options: A hân hoan B mỉm cười C giảm stress D lấp lánh E có thể cười 
Student:
C