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? ['bats use echolocation to catch insects and ttherefore gain no advantage from the fact that insects flying in the vicinity of streetlights are visible at night', 'in the absence of local concentrations of the flying insects on which bats feed, the bats expend much more energy on hunting for food, requiring much larger quantities of insects to sustain each bat', 'the bats do not begin to hunt until after sundown', 'the bats are unlikely to feed on insects that do not fly']