It is highly desirable that you furnish evidence of your expenses

OFFICIAL EXPLANATION

The good news is that we have yet another chance to dispel a myth.
(The bad news is that this myth resembles Hydra: chop off one head, and two grow back.)

hero_with_1000_faces , you ask a very good question. Answer:
There is nothing special about option A.

Some prep companies teach that option A determines the intended meaning.
Many older posts on many forums inaccurately repeat this same not-rule.
Option A does not determine the intended meaning.

The most logical, grammatical, and rhetorically effective sentence presents the intended meaning.
If that answer changes the meaning of A, that fact is fine.

Please see this post, here in which I give three official examples (of many) to demonstrate that option A does not determine intended meaning.

The three experts below collectively possess more than forty years' of experience teaching the GMAT. They say that there is nothing special about option A.
GMATNinja , HERE, Dmitry Farber, here, and Ron Purewal, HERE.

Very frequently we can figure out meaning from the non-underlined portion of the prompt, a fact that may make it seem as if option A determines meaning.
(To state the obvious: Option A is the underlined portion of the prompt.)

Option A may happen to fit grammatically and rhetorically 20% of the time, but that fact does not mean that option A is the originally intended meaning.

I have no idea why this myth is still being taught.
I have watched too many people reject a correct official answer because they believed it changed or seemed to change the meaning of option A, or because it was missing a word that (A) contained -- even though the rejected choice was grammatical and better than any of the other four answers including Option A.

One last time: There is nothing special about option A.
Okay, GMAT soldiers -- onward.

THE PROMPT


THE OPTIONS
• the subjunctive is used correctly
-- "It is desirable" is what I'll call a "bossy It Is" construction.
-- IT IS + [bossy adjective] + THAT + BASE VERB [that is, just use the infinitive "to furnish" without the "to"]
-- Correct, verb is in bare/base form: IT IS + desirable + THAT + furnish

For more on the command subjunctive, see bb here.
• This construction is hella awkward and stiff. Why is the writer using so many words?
• This sentence doesn't make a lot of sense.
Why is it just "highly desirable" that people submit expense receipts before their final accounts?
Isn't that situation the sort in which "supplying evidence" is mandatory?
KEEP, but look for a better answer.

• should is never used in command subjunctive on the GMAT.
-- Speakers of British English, be a little bit careful.
-- In B.E., the use of should is common in the command structure. That usage is not allowed on the GMAT.
-- This mnemonic might help you remember the rule: The command structure already implies should, so don't repeat yourselves.
REJECT B

• Option A's verbosity just got worse.
• evidence is a singular non-count noun.
-- There is no such thing as the noun evidences
-- We can have a lot of evidence, too little evidence, or sufficient evidence, but we cannot have "a lot of evidences." (We simply have a lot of evidence.)
REJECT C

• This option is grammatical and concise.
• This option is much better than option A.
-- It avoids the "it is" (expletive) construction, which can make sentences unnecessarily heavy and passive.
-- It is logical. Submitting receipts is not "highly desirable." Doing so is mandatory.
KEEP

• This option is too similar to option A.
-- Both (A) and (E) are tentative and use more words than are necessary
-- Neither option is as crisp as D
-- Neither is as logical as D.
Options A and E basically say that it's a good idea to give evidence of your expenses before you submit your final accounts, whereas Option D more logically states that submitting evidence of expenses before submitting final accounts is imperative.
Because A and E are too similar and because D is more logical,
REJECT E

The best answer is D.

NOTES

Up front: This question is not entirely fair, but it is a good opportunity to recognize that grammar rules alone will not be enough on SC.
GMAC would not give you option E, but it would give you options similar to A and D.

In that case, you would have to reason as I did between A or E on the one hand, and D on the other hand.
Style is hard to teach.
Sometimes hairsplitting examples that resemble this question help because they train you to compare options and develop your "ear."

COMMENTS

800GMAT2019 , fireagablast , rizzatoandrea , and Avinash514043 , welcome to SC Butler.

As always, I am glad to see all of you.
I like the dialogue.
I like critical thinking and sound reasoning, both of which everyone displayed, even though a few people relied on an inaccurate but much-taught assumption.

I am proud of all of you: you're engaged, you're reasoning well, and best of all, you are willing to make mistakes.
All of you gambled. Some of you got the wrong answer.
But all of you were brave.
Brave is good. Very good. Nicely done. Kudos to all.