We'll start this one by rereading about what the free rider effect is, and I'd recommend reading the sentences before to know exactly what's going on. So what is the free rider effect? If most countries cooperate to solve the problem, then anyone who didn't cooperate would be advantaged. They would have no extra costs and them alone not participating wouldn't have a really large effect. So we're looking for something where an agent doesn't act with the majority who is working to solve a problem, and then gets an advantage from it.
A) Not similar at all B) Not similar at all C) Here we have one agent acting outside the norm, but it is the one agent that is helping to solve the problem and they're not getting an advantage, so it doesn't match D) This one is closer because the homeowner is not participating in the group effort to solve the problem, but they're still paying for bottled water so they're not getting an advantage from doing this. E) This lines up. Everyone else is buying food for their animals in order to allow the fields to regrow, but this shepherd doesn't cooperate and lets his animals graze anyways. His advantage is that he doesn't have to pay for food, and him alone letting his animals graze probably won't cause a huge problem and the fields will still regrow.
