The question saying "progressive" without giving a time frame was a little confusing, as it means something different with GB than with things like MS or ALS. helpful, though, so thanks for the vid.
Yes - that is a good thing to point out. That is KEY on the test. They use wording that can apply to about three different diagnoses. So you can't use "progressive muscle weakness" or it isn't the best piece of information to use. Instead, look through the rest of the question to figure out what can definitively say "it is THIS answer, not THAT answer".
Good thought Claire. Yes they are separate before they merge together into one nerve root and exit through the intervertebral foramen. We can get really technical as to the location of the lesion, but on the test, they will generally stick to the entire nerve root. Plus, on the test, the nerve root lesions are often unilateral, making answer C a better choice because of the bilateral symptoms (both feet giving out). Finally, the L4 nerve root lesion would not have anything to do with abnormal Achilles reflexes as this is an S1 nerve root circuit.