[单项选择]Among the many other things it is, a portrait is always a record of the personal and artistic encounter that produced it. It is possible for artists to produce portraits of individuals who have not sat for them, but the portrait that finally emerges normally betrays the restrictions under which the artist has been forced to labor. Even when an artist’’s portrait is simply a copy of someone else’’s work-as in the many portraits of Queen Elizabeth I that were produced during her lifetime-the never-changing features of a ruler who refused to sit for her court painters reflect not only the supposed powers of an ever-youthful queen but the remoteness of those attempting to depict her as well. 　　Portraits are "occasional" not only in the sense that they are closely tied to particular events in the lives of their subjects but in the sense that there is usually an occasion-however brief, uncomfortable, artificial, or unsatisfactory it may prove to be-in which the artist and subject directly c
A. refute Avedon’’s conception about a portrait sitting.
B. provide one perspective of the portraiture encounter.
C. exemplify time restriction of the sitting for portraiture.
D. support the thesis on the uncertainty of a collegial sitting