The finding that senior citizens, unlike younger members of the population, tend to demonstrate relatively homogeneous sleep patterns suggest that there is a narrower time range in which people past retirement age are able to fall asleep and stay asleep.
(A) suggest that there is a narrower time range in which
(B) suggests that there is a narrower range of times in which
(C) suggest that there is a narrower range of times when
(D) have suggested that there is a narrower time range when
(E) and suggests that there is a narrower range of times in which
Scroll down for the answer.
Don’t be fooled by the presence of the plural noun patterns, which appears right before the underlined portion. In reality, the subject is the finding, singular. A singular verb is thus required, eliminating (A), (C), and (D).
(E) is incorrect because the placement of and before suggests creates a somewhat skewed meaning: this construction implies that senior citizens themselves (rather than their homogeneous sleep patterns) suggest that there is a narrower time range in which they can fall asleep.
(B) more logically implies that senior citizens’ homogeneous sleep patterns shed light on the difference between how older and younger people fall asleep.