Sentence Correction

On Earth, among the surest indications of sunspot cycles are believed to be the rate that trees grow, as seen in the rings visible in the cross sections of their trunks.

(A) On Earth, among the surest indications of sunspot cycles are believed to be the rate that trees grow
(B) On Earth, among the surest indications of sunspot cycles are, it is believed, the rate of tree growth
(C) On Earth, the rate at which trees grow is believed to be among the surest indications of sunspot cycles
(D) Among the surest indications on Earth of sunspot cycles, believed to be the tree growth rate
(E) Among the surest indications on Earth of sunspot cycles is believed to be the rate at which trees grow


OA E

Source: GMAT Prep

In this sentence, there is an issue of comparison. The sentence doesn't really compare the time period appropriately.

Option A - Incorrect
This compares the population of the blue heroes to the 1970s

Option B - Incorrect
This option compares the population of the birds to the birds to the 1970s.

Option C - Correct
It completely avoids the wrong comparison by explaining the sentence in a correct manner both grammatically and logically.

Option D - Incorrect
Using words like 'those and that' in making a comparison creates a new copy so you have to add additional info as to why the new copy is different from the other one.

Option E - Incorrect
It has the same issue as option D. The use of 'that' creates an ambiguous statement.