by Sage Pearce-Higgins Fri May 04, 2018 5:19 pm
Since this is an 'according to the passage' question, we're looking for something the answer choice that is actually stated in the passage. For these type of questions, looking for the right answer, rather than eliminating wrong answers, can be a faster route. The relevant sentence here is 'Evidence that pheromone responses may not involve conscious odor perception comes from the finding that in many species, pheromones are processed by the vomeronasal (or accessory olfactory) system...'
I can see that answer B is tempting, as we're told that 'the distinction between pheromones and odorants...can be blurry'. However, the fact that pheromones are, for most species, processed by the VMO actually acts as evidence against the blurry distinction. I mean, if odorants are processed one way, and pheremones are processed another way, then the distinction is clear.
One of the clues in this question is the phrase 'has been taken as evidence'. This shows that we're not just looking for any old thing stated in the passage, but for a connection between evidence and claim. That might help guard against answer B.