the use of "authorities" to refer to people is standard; i can't imagine that the gmat would object to that usage. if any users here have seen evidence in an official problem either confirming or denying this, please post.

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this question is ok, because the other 4 choices are all ungrammatical.

(a) is incorrect because it's unidiomatic (or redundant, depending on how you look at it).
* you could say that it's unidiomatic, because you're not allowed to use "should" with the verb "request".
* you could also say that it's redundant, because the word "request" already carries the implicit meaning of "should" (or is at least related). therefore, you are to use only one of these two words:
they requested that you come to the meeting.
they said that you should come to the meeting.

(b) is unidiomatic: you can't say "request PERSON to INFINITIVE". it must be written in the command subjunctive, as in choice (d).

the literal meaning of (c) is that the museum rebuffed the authorities and separately rebuffed a request. moreover, the pronoun "its" doesn't refer to anything valid; the only possible "it" is the british museum itself, absurdly suggesting that the museum rebuffed its own request.

(d) is correct.

(e) is wrong for the same reason as (b).

goelmohit2002 wrote:Thanks Ron.

Another reason, I think we can kick out "B" and "E" based on "them" too..since museum is singular.

yes, good.

i didn't even look that far, because of the flagrantly incorrect idiom.

well done.