Using the prisoner's dilemma theory

The class can have a bonus point of 2 or 6 in the test. If all of the students choose 2-point bonus, all of them will get 2 points. If more than 10% of students choose 6-point bonus, no one gets a bonus mark. If less than 10% choose 6-point bonus, they will get the 6 bonus points and the rest would only have 2. In this case, what do you think is the best solution?