This is a strengthen question, meaning we are looking for an answer choice that provides the most support for the argument.
Let's briefly look at the structure of the argument.
Premise:
Eight years ago hunting was banned because it endangers public safety. Now the deer population is six times what it was before the ban, and deer are causing damage in the area. There were never any hunting-related injuries in the county.
Conclusion:
The ban was not only unnecessary but has created a danger to public safety that would not otherwise exist.
This conclusion has an implied assumption that the hunting ban contributed to the deer population explosion that would not have happened otherwise.
Let's look at the answer choices.
(A) is the correct answer choice because the fact that the deer population in nearby counties where hunting is permitted has not increased supports our assumption that there is a causal relationship between the size of the deer population and hunting, and the deer population would not have increased dramatically if not for the hunting ban.
(B) is incorrect because it merely restates one of the premises but it fails to demonstrate the hunting ban did in fact result in deer population increase and the corresponding danger to public safety.
Does this make sense? Let me know if you have any other questions.