Hello Everyone!
This is a difficult question, so let's dive in! First, take a quick look at the question and highlight any of the major differences between the options in orange, so we can focus on those later:
In no other historical sighting did Halley's comet cause such a worldwide sensation as did its return in 1910-1911.
(A) did its return in 1910-1911
(B) had its 1910-1911 return
(C) in its return of 1910-1911
(D) its return of 1910-1911 did
(E) its return in 1910-1911
Since this is such a short sentence with such short options, let's just focus on the type of question this is: COMPARISON!
Whenever we see comparisons like this, an easy trick to try is to reword it with the two items compared sitting next to each other:
Original Sentence: In no other historical sighting did Halley's comet cause such a worldwide sensation as did its return in 1910-1911.
Reworded Sentence: Halley's comet caused such a worldwide sensation in no other historical sighting as did its return in 1910-1911.
No matter how you word this sentence, it's clear that the two items being compared are the original sighting of Halley's comet and its return in 1910-1911. When looking at each sentence, let's make sure that the two items are parallel:
(A) In no other historical sighting did Halley's comet cause such a worldwide sensation as did its return in 1910-1911.
(B) In no other historical sighting did Halley's comet cause such a worldwide sensation as had its 1910-1911 return.
(C) In no other historical sighting did Halley's comet cause such a worldwide sensation as in its return of 1910-1911.
(D) In no other historical sighting did Halley's comet cause such a worldwide sensation as its return of 1910-1911 did.
(E) In no other historical sighting did Halley's comet cause such a worldwide sensation as its return in 1910-1911.
Well that was quick - the only sentence that compared two parallel items is option C! Whenever you see a comparison question on the GMAT, parallelism is a great place to start. Parallelism is the most common problem with comparison questions, even if the sentence is long-winded or complicated!
Don't study for the GMAT. Train for it.
