You’re right- this is tricky without more information! I’m going to copy something over that I just responded to another forum question because I think it applies here:
As long as you can justify your reasoning, I think you will find you are in great shape for the NCS and clinical practice. Obviously, you can’t make your case on the NCS exam, but there won’t be enough questions like this for them to make or break whether you pass – and being able to defend your answer means it wasn’t a wild guess and that increases your chances of being correct.
You will find some NCS exam questions are testing whether you’ve read a specific article (like this question). However, that doesn’t mean you should try to read every article. The time spent chasing small details that may or may not appear on the exam would detract from your focus on the big topics that will definitely comprise a large portion of the exam (think your big neuro diagnoses).
Being able to formulate your best answer to one of those detail questions, then forget about it and move on to the next question with complete focus will serve you well! This is a good practice question to rehearse that skill as much as it is to test whether you’ve read the Fritz and Lusardi article.