Answer:
Option A is the correct answer (Area Residents)
Step-by-step explanation:
The area residents would gain from the benefits of having a cleaner water resources and they would be the one to enjoy thriving from a unique and thriving ecosystem.
A free rider is simply a person or group of people benefiting from a program without having to put any effort or pay a dime for it. In this light, it can be seen why the area residents are the free riders from the example.