Answer: The cost of something is what you give up to get it
Step-by-step explanation:
The options to the question are:
1.) The cost of something is what you give up to get it
2) Markets are usually a good way to organize economic activity
3) People usually exploit opportunities to make themselves better off.
4) Trade can make everyone better off
This has to do with opportunity cost whereby there's always a trradeoff between two goods. One has to make a choice and leave out one economic decision in order to make another decision.
This can be seen in the question where we were told that In order to swim for an hour, Paolo must take time away from work, where he earns $11 per hour. This is in addition to paying a $4 entrance fee for the pool.