Even within the same study, people responded quite differently to

Solution: E

Explanation: In this type of sentence correction problem you need to focus on parallelism and verb form. At the end of the sentence, if you say “did not” you should ask “did not” what? The general rule is that there needs to be a verb that is being replaced by “did”. In this example, there isn’t a verb, just a participle, so the structure would not be parallel: You cannot say “some showing this, while others did not show this” or “some showing this and others did not show this” As a result, (A), (B), and (C) are all incorrect.

In (D), you would need a complete clause after while with a comma and all you have is “while others not showing”

Only (E) creates a parallel structure with two participles following nouns after the preposition “with” (the second participle is understood): “with some showing this and others not showing this”

Answer is (E).

https://well.blogs.nytimes.com/2013/04/26/ask-well-do-we-need-to-stretch/

Some have had young, healthy volunteers stretch for 20 minutes or more, others for 5 minutes or less. Still others have used older, stiffer volunteers or people with existing injuries. Not surprisingly, the results have been inconsistent. Even within the same study, people respond quite differently to stretching, with some showing increased flexibility and others not.