Accurately solving requires understanding what is the intended comparison. We're not comparing comets, or even sightings of the comet. The author seeks to compare the extent to which the comet causes a sensation in the 1910 sighting vs the extent to which it caused a sensation in any other sighting ; this is a comparison of actions.
The 1st non-underlined part (simplified) is "Never did the comet cause such a sensation..." the ideal, parallel comparison would end with "as it caused in 1910". Only answer C provides an even comparison.
C is correct.
A, B and D fail to convey that
the comet causes the sensation. Instead they imply that the comet's
return causes the sensation.
E fails to compare actions.
Another way to see why C is correct is to realize that for parallelism's sake, "
in no other sighting" should be compared with "as
in the 1910 return". This alone should eliminate most answers.
A
much more detailed explanation can be found at
GMATPrep Question 2087. To practice similar questions in a timed exercise, set topic='Parallelism, Comparison' and difficulty='700+' in the Drill Generator.
Good luck,
-Patrick
