RBBmba@2014 wrote:@Verbal Experts - although I got this one, I'd like to know that why EXACTLY option B is wrong ?
IMO, what option B says is either IRRELEVANT or out of scope to what we're looking for because we're NOT concerned with whether bats eat only flying insects or non-flying insects as well.

Correct me please if wrong!

B is a trap answer that might tempt someone who is not really paying attention to what the prompt is saying.

While the prompt does mention flying insects, the distinction being made is not between insects flying and insects not flying. It's between flying insects being attracted to the lights or not attracted to the lights. So, while I guess one could somehow create some story that would connect what B says to what the prompt says, creating such stories is not the way to get GMAT CR questions right, and, as you said, the fact that bats are unlikely to feed on insects that do not fly has little to no direct relevance to what is being discussed.

RBBmba@2014 wrote:When mercury-vapor streetlights are used in areas inhabited by insect-eating bats, the bats feed almost exclusively around the lights, because the lights attract flying insects. In Greenville, the mercury-vapor streetlights are about to be replaced with energy-saving sodium streetlights, which do not attract insects. This change is likely to result in a drop in the population of insect-eating bats in Greenville, since ___________________________________

Which of the following most logically completes the argument below?

(A) the bats do not begin to hunt until after sundown
(B) the bats are unlikely to feed on insects that do not fly
(C) the highway department will be able to replace mercury-vapor streetlights with sodium streetlights within a relatively short time and without disrupting the continuity of lighting at the locations of the streetlights
(D) in the absence of local concentrations of the flying insects on which bats teed, the bats expend much more energy on hunting for food, requiring much larger quantities of insects to sustain each bat
(E) bats use echolocation to catch insects and therefore gain no advantage from the fact that insects flying in the vicinity of streetlights are visible at night

OA:D

Source: OG Verbal 2016,CR Qs.50

@Verbal Experts - although I got this one, I'd like to know that why EXACTLY option B is wrong ?
IMO, what option B says is either IRRELEVANT or out of scope to what we're looking for because we're NOT concerned with whether bats eat only flying insects or non-flying insects as well.

Correct me please if wrong!

B is completely out of scope here.

Premise: mercury-vapor streetlights attract insects and Bats feed on them. energy-saving sodium streetlights do not attract insects, hence Bats will not be able to feed.

We are not making any distinction between flying and non flying insects. No where it is written that bats eat only flying insects.

Does this help?