This is a question with answer options. What kind of thing would the answer to the question "What writer is famous for physically putting himself into the center of his subject matter ?" be an entity, an abbreviation, a description, a human, a location, or a numeric value?

Possible answers:
 a). description.
 b). entity.
 c). abbreviation.
 d). human.
 e). numeric.
 f). location.
d).