I Don't understand why the cost of books is excluded from your opportunity cost.

36 If your tuition is $2,000 this semester, your books cost $400, you can only work 10 rather than 40 hours per week during the 15 weeks you are taking classes and you make $12 per hour, and your room and board is $4,000 this semester (same as if not attending college), then your opportunity cost of attending college this semester is O A) $2,400. O B) $2,760. O C) $7,800. OD) $11,800. Table for Individual Question Feedback Points Earned: 0.0/2.0