Why does the author introduce Abstract Expressionist painter
A．He wants to provide an example of artists who, like serious contemporary photographers, disavowed traditionally accepted aims of modern art.
B．He wants to set forth an analogy between the Abstract Expressionist painters and classical Modernist painters.
C．He wants to provide a contrast to Pop artist and others.
D．He wants to provide an explanation of why serious photography, like other contemporary visual forms, is not and should not pretend to be an art.