請依下文回答第 17 題至第 20 題Visitors to art museums are often overwhelmed by the number of works on display, and by what they take to betheir own culpable inability to concentrate on more than a few of these works. In fact such a reaction is altogetherreasonable. Art history has totally failed to come to terms with the problems of the relationship between theoutstanding work and the average work of the European tradition. The notion of Genius is not in itself an adequateanswer. Consequently the confusion remains on the walls of the galleries. Third-rate works surround an outstandingwork without any recognition—let alone explanation—of what fundamentally differentiate them.The art of any culture will show a wide differential of talent. But in no other culture is the difference between‘masterpiece’ and average work so large as in the tradition of the oil painting. In this tradition the difference is not justa question of skill or imagination, but also of morale. The average work was a work produced more or less cynically:that is to say the values it was nominally expressing were less meaningful to the painter than the finishing of thecommission or the selling of his product. Hack work is not the result of either clumsiness or provincialism; it is theresult of the market making more insistence demands than the art. The period of the oil painting corresponds with therise of the open art market. And it is in this contradiction between art and market that the explanations must be soughtfor what amounts to the contrast, the antagonism existing between the exceptional work and the average.
17 What is the main idea of this passage?
(A)The European tradition of oil paintings displayed in museums.
(B)The problem in distinguishing outstanding and average works of art.
(C)The irresponsibility of gallery and museum employees.
(D)The inability of museum visitors to appreciate arts.