
Reply

Ravi December 26, 2018
@samarrastia001,This is a great question. Answer B is wrong for both using AND instead of OR and for using a necessary condition as a sufficient condition. It's far different from the valid argument structure that appears in the stimulus and answer choice C.
You mentioned that these questions sometimes take a lot of time for you. Your ability to eliminate answer B after reading that it was using AND instead of OR is fine, as we know from reading the stimulus that we have to see an OR in the answer choice. Your strategy is fine.
If you'd like extra assurance, take note of questions like this where you're finding that you're eliminating wrong answers very quickly, and track your accuracy on these questions. You'll likely find that your accuracy is quite high (you sound like you have a strong grasp of conditional logic), and this will further boost your confidence.
Does this answer your question? Let us know if you have any other questions!