Linguist: One group of art critics claims that postimpressionist paintings ... ...

Linguist: One group of art critics claims that postimpressionist paintings are not really art and so should be neither studied nor displayed. Another group of critics disagrees, insisting that these paintings are works of art. But since the second group grants that there are paintings that are not works of art and should therefore be ignored in the manner suggested by the first group, their disagreement is not over the meaning of the word “art.” The claim that there are paintings that are not works of art plays which one of the following roles in the linguist’s argument?
(A) It is a contention that the argument purports to show is the main point of disagreement between the two groups of critics mentioned.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Oct 2012 LSAT (PT67): Logical Reasoning B