Official Explanation Magoosh:
(A) There are a couple of issues, both very subtle, going on here. First off, “the maintaining” is not doing the overlooking. Yes, this is very nitpicky, and, in of itself, would never make or break an answer. Coupled with the second issue, however, we have an answer choice that falls short of being the best answer. The second issue is the comma between “cohesion” and “overlooks”. We do not want a comma to separate the noun phrase from its verb. To make this easier to see, get rid of the phrase set off by commas (“in adhering to a stream…”). This level of subtly is only something you’d see on the most difficult SC questions.
(B) Here we have a blatant change in meaning: Woolf is now doing the “overlooking”.
(C) The two verb forms, “to maintain” and “to overlook” are parallel to indicate a logical comparison: To do X is to do Y. The absence of a comma between “cohesion” and “is” correctly highlights this logical comparison (A comma would have represented an unnatural break: To do X, is to do Y”
(D) In lacking an actual verb to the sentence (overlooking is a participle), (D) results in a sentence that is not actually a sentence.
(E) creates a disruption between “forced” and “to”. Perhaps more salient is the fact that the meaning, “forced in adhering to a stream-of-conscious style”, is changed to “forced in sacrificing unity…to adhere to a stream-of-conscious…”