Read the excerpt from The Call of the Wild. Thornton's doubt was strong in his face, but his fighting spirit was aroused—the fighting spirit that soars above odds, fails to recognize the impossible, and is deaf to all save the clamor for battle. He called Hans and Pete to him. Their sacks were slim, and with his own the three partners could rake together only two hundred dollars. In the ebb of their fortunes, this sum was their total capital; yet they laid it unhesitatingly against Matthewson's six hundred.

What do the slim sacks represent?

the unlikeliness of Buck being able to do the task
the disrespect that the onlookers have for Thornton
the ridiculousness of the wager made by Matthewson
the inability Matthewson has to get people to wager