Hi tanvis1120,

Most SCs are built around 2-4 grammar "issues" for you to work with, so if you find yourself unsure on 1 of the issues, you can look for other (possibly easier) issues to deal with that will help you to eliminate whatever wrong answers remain.

In this SC, I think that you correctly eliminated the first three answers because the Modification was incorrect. With the remaining two answers, if you're unsure about how to quantify "amount(s) of sleep" (singular or plural)....take a look at the phrase "and also" in Answer E.

"And also" is redundant; you don't need both of those words. Eliminate E.

GMAT assassins aren't born, they're made,
Rich

Jim is wrong here.

"Adequate amount" and "adequate amounts" would both be correct in this context. It is perfectly correct to talk about the "adequate amount of calcium needed for growing children," even though "children" is plural. The discrepancy - if one even exists - is that "amount" might refer to a single, agreed upon amount: exactly 8 hrs per person, per night, for example. "Amounts" might suggest that the amount of sleep might vary by person or by night.

This is what we call a RED HERRING split - intended to distract us, but not making a meaningful distinction between answer choices.

As Rich mentioned, the first 3 answer choices can be eliminated because the initial modifying phrase incorrectly modifies "people's." In E, in addition to the redundancy of "also," "the adequate amount they need" is also redundant. Thus, we're left with D.

As usual, the goal appears to be responding as quickly as possible, to maintain the "most responsive" grade, regardless of accuracy. Sigh...

-t