Despite the increased interest in automobile racing, the plummeting at

OFFICIAL EXPLANATION



Despite the increased interest in automobile racing, the plummeting attendance figures at local races fell so low that the owner was forced to close the speedway.


• Redundant. The word plummeting already establishes that the attendance figures have fallen and are low.
• Plummeting means decreasing quickly by a large amount, HERE
• Either "fell so low" or "plummeting" must go. "Plummeting" is not underlined. "Fell so low" should be removed.
• so low that the owner was forced to close is a trap. The idiom So X that Y would be fine if it were not redundant.


• also redundant as in (A)
• low enough that + clause is a different kind of trap. T
Be careful with enough. I do not know of a single official question in which the correct answer included "enough that." I know of three in which the correct answer did not include enough that.
One official question is HERE. Another is HERE
In the last example, the OE writer mentioned vaguely that "enough that" was not as idiomatic as So X as to YHERE


• correct


• redundant as in A and B
• no reason exists to use had been forced, the past perfect tense

]
• the attendance figures did not close the speedway. The owner closed the roadway.

Answer C

Redundancy may be difficult to catch in this question.
When redundant words are separated from each other, catching the redundancy is harder than when the words are close together.

We can eliminate D for its use of past perfect and E for illogical meaning.
Option B is not idiomatic. ("Enough that" is very common in speech and in informal writing. The construction is not correct on the GMAT.)
Now, A or C?

Remember that plummeting is an adjective. It tells us that attendance figures had fallen very quickly and were low.
Plummet is a dramatic verb.
In English we say, "Skyrocketing interest rates hurt the housing market."
We also say, "Plummeting attendance rates forced the owner to close the roadway."
We don't need the extra words in A, let alone redundant extra words.

COMMENTS

vaibhav1221 , Peddi , and rimkahan , welcome to SC Butler.

As always, I am please to see familiar usernames, too.

I am glad to see that so many people track on meaning.

A couple of you slid in after the OA posted. I haven't been explicit, so you get kudos. I will be clearer about time constraints.
If you posted before my edit, you get kudos.
Correct answers with explanations get kudos. Finally, if you got the answer wrong but I think you demonstrated good effort, you also get kudos.
Enjoy the rest of your weekend.