The use of (a) in a story attaches deeper meaning to a person, object, or place.

narrative voice
satire
symbol
tone

Which excerpt from "the most dangerous game" best portrays zaroff as rainsford’s foil? "but no animal can reason," objected rainsford. "my dear fellow," said the general, "there is one that can." "but you can't mean—" gasped rainsford. "and why not? " "why should i not be serious? i am speaking of hunting." "hunting? general zaroff, what you speak of is murder.” "and if they win? " the smile on the general's face widened. "to date i have not lost," he said.