Answer:
opportunity cost
Step-by-step explanation:
The opportunity cost is the cost that is incurred for purchasing any other thing in place of one thing or we can say it is a sacrification done to purchase another thing
Here in the question it is mentioned that the Lil spent $120 for purchasing a new sweater instead of buying her finance textbooks also the cost of buying the sweater is known as the non doing textbooks cost
So here it is a opportunity cost