Some critics claim that it is unfair that so many great works of art

"Some critics claim that it is unfair that so many great works of art are housed in huge metropolitan museums"
"But this criticism is in principle unwarranted because the limited number of masterpieces makes a wider distribution of them impractical."

(D) For it to be reasonable to criticize an arrangement as unfair, there must be a more equitable arrangement that is practically attainable.

=> Choice D

The right answer is D.

Premise: Some critics claim that it is unfair that so many great works of art are housed in huge metropolitan museums, since the populations served by these museums already have access to a wide variety of important artwork.
Counter-premise: The limited number of masterpieces makes a wider distribution of them impractical. Besides, if a masterpiece is to be fully appreciated, it must be seen alongside other works that provide a social and historical context for it.
Conclusion: This criticism is in principle unwarranted.

Per the argument above, some critics claim that the placement of many great works of art in huge metropolitan museums is unfair on the basis that the audience of these museums already has access to a variety of important artwork. But the author says that this criticism is unwarranted. Why? The number of great works of art are limited, thereby making their wider circulation impractical. The author proceeds further by providing a justification as to why the placement of the artworks in the metropolitan museums.

We are to determine which answer choice, if established, could most logically serve as the principle appealed to in the argument countering the critics’ claim.

Option D states that for it to be reasonable to criticize an arrangement as unfair, there must be a more equitable arrangement that is practically attainable. This is the right answer. The author basically rejects the criticism of the critics that the placement of the masterpieces in Metropolitan museums is unfair because in his/her view, there is no better alternative to the current placement. The limited number of artworks means they cannot be widely circulated and the artworks would derive better value if they are placed beside other works that provide historical and social context to them.

(A) In providing facilities to the public, the goal should be to ensure that as many as possible of those people who could benefit from the facilities are able to do so.
This is not correct because the argument made by the author does not proceed in the manner stated in A. At best, A seems to somehow strengthen the position of the critics.

(B) In providing facilities to the public, the goal should be to ensure that the greatest possible number of people gain the greatest benefit possible from them.
B is incorrect for the same reason as A is incorrect.

(C) It is unreasonable to enforce a redistribution of social goods that involves depriving some members of society of these goods in order to supply others.
This does not in anyway mimic the principle applied by the author to counter the argument made by the critics.

(E) A work of art should be displayed in conditions resembling as closely as possible those in which the work was originally intended to be displayed.
E resembles the second premise provided by the author to justify the placement of the artworks in Metropolitan Museums, but this is not the main criticism provided to counter the argument made by the critics. E is therefore not the right answer.

Critics say that displaying art in museums located in the metropolitan cities makes the art accessible for the people who already have access to similar artworks.

The [b]author [/b]says that a limited number of works makes it impossible to distribute them in different places, also he adds that artwork can be appreciated & better understood if it is placed alongside similar works.

The question asks us to find the option that logically supports the authors claim,

Answer choice analysis:
a) This choice supports the critics claim that the work should be available to the vast majority of audiences (Wrong)
b) Similar to choice a (Wrong)
c) Similar to critics reasoning (wrong)
d) This choice says that to prove something as unfair, it should be done contrasting it with a feasible alternate Idea.
This is not what the author says. (Wrong)
e) Similar to the author's line of reasoning. (Correct)

(D) For it to be reasonable to criticize an arrangement as unfair, there must be a more equitable arrangement that is practically attainable.......clearly counters the claim made by the critics which is impractical and not clear

OA:D

Some critics claim that it is unfair that so many great works of art are housed in huge metropolitan museums, since the populations served by these museums already have access to a wide variety of important artwork. But this criticism is in principle unwarranted because the limited number of masterpieces makes wider distribution of them impractical. Besides, if a masterpiece is to be fully appreciated, it must be seen alongside other works that provide a social and historical context for it.

Which one of the following, if established, could most logically serve as the principle appealed to in the argument countering the critics’ claim?

This is a tough one.
Here Question is basically asking to look for something that goes against critics claim i.e. weakens it. A point to note author here goes against critics claim. A catch here might be that we may think of going with the author but it is not necessary that it would be against critics claim.

So, we must look specifically into critics claim to weaken it. Critics claim as put forth by author here is that they are in favor of more people being able to use it as it is unfair since people who already have access to important artwork are being serve by the museums.

A and B are strengtheners, B being larger in scale with a slight variety in approach.
C talks something on moral grounds which is anyhow wrong. Hence irrelevant.
E basically goes against author's opinion instead of critics'.

D is the answer since author's opinion was against critics' considering practicality and here D does say that what critics say should be practical, one of the two things that author talks about.

IMO Answer D.