Question

question 2
the opportunity cost of an activity is
○ zero if you choose the activity voluntarily.
○ the amount of money spent on the activity.
○ the value of the best alternative not chosen.
○ the sum of benefits from all of the alternatives not chosen.

Explanation:

Opportunity cost is defined as the value of the next - best alternative that is forgone when a choice is made. It is not about the money spent on the chosen activity (that is explicit cost in some cases), nor is it the sum of all alternatives (because we consider the best alternative), and it is not zero just because the activity is chosen voluntarily.

Answer:

the value of the best alternative not chosen.