The second paragraph makes use of which of the following

A．They constitute an innovative art form.
B．They can be a worthwhile subject for study.
C．They are critically important to an understanding of modern art.
D．Their visual structure is more complex than that of medieval art.

A．They do not believe that illusionist tricks have become trivial.
B．They generally spend little time studying contemporary artists.
C．They have not given enough consideration to how the representation of nature has become commonplace.
D．They generally tend to argue about theories rather than address substantive issues.