How could their incentives backfire? For at least 3 behavior-incentive pairs they listed, discuss and explain their possible consequences

There are some incentives a professor can give their students to encourage them to work efficiently, diligently and execute. 1. Give extra credit for completing assignments early 2. Relieving individuals of the final exam if student maintained a 90 or higher the duration of the term, student can be exempt from exam. 3. The top 3 students will be placed in a raffle to win a grant applicable to tuition, books, fees etc., (that's if professor has resources of such.) 4. Attend at least 3 remote study session and you can receive a letter of recommendation