GMAT Sentence Correction (SC) | Re: Whereas a typical Master's thesis is approximately one hundr

Eliminated A (because thesis is compared to theses) and C (because of "so a").

Then I eliminated D because it does not have "generally" or "usually" at the end.

Felt B was better than D because "thesis" is being compared to "thesis".

B) A typical Master'sthesis is approximately one hundred pages long, while a Ph.Dthesis is generally
D) While typical Master'stheses is approximately one hundred pages long, Ph.Dtheses is generally
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