How does the sentence "if you want to succeed at whist, either be a good whist-player, or play with marked cards," develop the writer's claim?
a) it echoes the overall claim of the passage, to discount the need for books about success.
b) it serves a contrast to the real message about success, that it comes to those with great virtue.
c) it develop the idea that to gain success is to read lots of books by writers who truly understand success.
d) none of these choices explain how the sentence develop the writer's claim, as the overall claim is unclear throughout the passage.