You have to be careful, Pankaj0901, not to follow grammar so closely that you miss out on the logical meaning that is conveyed by the sentence as a whole. I am guessing you tested (E) in the following manner without considering the rest of the sentence.

attempts to discern the best options among [options'] potential uses

As a parallel, think of studying plants to find potential remedies for ailments. Such a sentence might adopt a similar construct:

attempts to discern the best remedies from among their potential uses

Grammatically, you might point to remedies as the closest plural noun, but then why would the sentence be talking about deriving remedies from plants? Again, consider the whole sentence. A strictly grammatical approach will help you answer many questions correctly, but at the same time, many upper-level questions rely more on the clear and concise expression of vital meaning to arrive at a correct answer. (With this in mind, I wrote this question for the 12 Days of Christmas Competition a couple months ago. My explanation is right beneath the question itself.)

I hope that helps. Thank you for following up from one of my earlier posts. I like to add clarity to the discussion as often as needed.

- Andrew

Thankyou AndrewN