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 ttherefore 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? ['It is a contention that the argument purports to show is the main point of disagreement between the two groups of critics mentioned.', 'It is a claim whose acceptance by critics who differ on other issues is cited by the argument as evidence of its truth.', 'It is a claim whose acceptance by both of the two disputing parties is cited as evidence for a conclusion the argument draws about the disagreement.', 'It is cited as a commonly accepted reason for accepting a hypothesis for which the argument offers independent evidence.']