Answer:
The correct answer is that the opportunity cost of attending classes is doing something entirely different with that same time.
Step-by-step explanation:
First of all, we understand the opportunity cost is an economic concept that helps us to take better decisions and that is why it is focus on what we lose in order to gain something else. That is why, the opportunity cost of attending classes is the time the person can spend in doing something else, like hanging with friends or working. Therefore that this type of cost what focus on is in the other situation that could be happening but is not due to our decision made and that represents the sacrifies made in order to obtain what the person choose.