The heart of this question is that we’re trying to compare the fact that the newspapers had a lower circulation “in the six months from October 1995 through March 1996” than… well, we’re trying to compare the circulation in one period to the circulation “in a similar period”, so that should lead us to the right answer pretty quickly.
Quote:
(A) a similar period
The comparison isn’t quite right here. The newspapers “had lower circulation
in the six months from October 1995 through March 1996 than
a similar period a year earlier.” Nope, we would need to say that the circulation was lower
in a similar period for this to make sense.
(A) is out.
Quote:
(B) a similar period’s
(B) basically gives us the same mistake as (A), except that now “period’s” is possessive. I guess it’s trying to possess “circulation”? Can a “period” possess “circulation”? Seems wacky to me.
Even if we give it the benefit of the doubt, that leaves us with “… newspapers had lower circulation
in the six months from October 1995 through March 1996 than
a similar period’s circulation a year earlier.” That’s not completely illogical, I guess, but it doesn’t cut to the heart of the comparison – we’re trying to emphasize the difference in circulation
in the two periods. And that possessive thing still strikes me as weird.
If you really wanted to be conservative, you could keep (B), but we’ll have a better option in a moment.
Quote:
(C) in a similar period
This is about as clear as it can get: “… newspapers had lower circulation
in the six months from October 1995 through March 1996 than
in a similar period a year earlier.” That cleanly compares the circulation in one period with circulation in another.
So let’s keep (C).
Quote:
(D) that in a similar period
In this context, “that” is trying to act as a singular pronoun. (More on the
GMAT’s many uses of “that” in this article.) I guess “that” refers back to circulation, so that gives us: “… newspapers had lower circulation
in the six months from October 1995 through March 1996 than
the circulation in a similar period a year earlier.”
That’s not necessarily illogical, but it’s a waste of words. (C) is more succinct, and I can’t figure out why we would need to repeat the word “circulation” – or a pronoun that refers back to the word “circulation” – in this sentence.
So (C) is still better than (D).
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(E) that of a similar period
And (E) is just a crappier version of (D). There’s no need to include the word “that” here, but it also doesn’t make sense to talk about “the circulation
of a similar period.” We could talk about “the circulation of a newspaper”, because the newspaper itself “circulates” (i.e., the newspaper is distributed among the population), but we wouldn’t circulate “a period.”
So (E) is out, and we’re left with (C).