Dear Friends,

Here is a detailed explanation to this question-



Choice A: In Option A, we see a subject-verb disagreement between "amounts" and "a sum". Thus, Option A is incorrect.

Choice B: Option B displays the same flaw that Option A does. Thus, Option B is incorrect.

Choice C: Option C maintains correct idiomatic usage and subject-verb agreement. Thus, Option C is correct.

Choice D: In Option D, the sentence compares two amounts. As "amount" is uncountable, the correct adjective to use here is "less" rather than "lower'. Thus, Option D is incorrect.

Choice E: In Option E, using both "amounted to" and "sum" is redundant; when the verb “amounted to” is used, it is understood that that the end result will be a sum. Thus, E is not a good answer choice.

Hence, C is the best answer choice.

To understand the concept of “Collective, Countable, and Uncountable nouns on GMAT”, you may want to watch the following video (~2 minutes):



All the best!
Experts' Global Team
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Exactly - if I have $47.65, then I have less than $50, as the value of money doesn't have to be in integer form.

But if I have 47 dollar bills, then I have fewer than 50 dollar bills, as the number of bills can only be expressed as an integer.

Nice work! And if you really want more on countable vs. non-countable modifiers, here's an excessive video on the topic.
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GMATNinja
So, can I say the following?
2 (integer) is fewer than 5.
or,
2.5 (fraction) is less than 5.