According to most researchers, working during the school year leads to a significant and negative impact on academics (e.g. cheating on exams, absences, and decrease likelihood of graduation) when the amount of work is more than how many hours per week?

1. only when they spend more than 30 hours a week working

2. 20 or more hours a week working

3. 10-15 hours a week working

4. as little as 5-10 hours a week working can lead to these types of academic problems