Bunuel
In the twentieth century, the visual arts have embarked on major experimentation, from cubism to expressionism. While tastes always vary, there are certainly some people who find beautiful objects of each of the art movements of the first half of the twentieth century. In the latter half of the twentieth century, though, most works are so abstract or shocking that neither the critic nor the general public uses the word "beautiful" to describe them: indeed, sometimes late twentieth-century artists have, as one of their expressed goals, the creation of a work that no one could find beautiful. Whatever these artists are creating may be intellectually engaging at some level, but it is no longer art.
Which of the following is an assumption that supports drawing the conclusion above from the reasons given for that conclusion?
A. Art critics generally have a different appraisal of a work of art than does the general public.
B. The meaning of any work of art is defined entirely by the ideas of the artist who created it.
C. Beauty is a defining quality of art.
D. All art movements of the latter half of the twentieth century are responses to the movements of the first half of the century.
E. It is not possible for any work to be simultaneously beautiful and intellectually engaging.
Official Explanation
The argument makes a number of factual statements. Art in the first half of the 20th century are, or could be considered, beautiful. Works by artists in the latter half of the 20th century are not supposed to be beautiful, and even, are supposed to be devoid of beauty. Then the argument draws a bold powerful conclusion: therefore, they are not art! The assumption seems to be something that links beauty to whether something qualifies as art. We definitely need an answer to speak to the question: what does, or doesn't, qualify as art?
(C) is credited answer. If something needs to be beautiful, or potentially beautiful, to qualify as art, then this would explain that works that "no one could find beautiful" would fall outside the author's definition of art.
The other answers are all quite tempting, because we could imagine an art professor or someone in an art class arguing for any one of them.
(A) is irrelevant. Critics & the general public might have different appraisals, but what one or the other thinks does not, in and of itself, seem to determine whether something is art.
(B) is also irrelevant: who determines the meaning is a separate question from whether the work qualifies at art in the first place. (BTW, exceedingly few modern critics would accept the interpretive idea contained in choice .)
(D) is undeniably true, but not relevant: again: it provides no standard by which we could say the former objects are art and the latter objects aren’t.
(E) is a far-flung idea, unrelated to the discussion. The passage doesn't address the issue of whether any works of art are intellectually engaging.