Task: Question Answering
Input (English): Minnesota "Doc" West is sending money (each bill marked with an "E") to a  boarding school in Boston in a post office at Santa Fe, New Mexico. After leaving the post  office he is robbed by two bandits who take everything, including his money. He rides after them on his horse, but is stopped when he sees a boy named Silver fall  off his horse spooked by a rattlesnake. West shoots the rattlesnake's rattler off and it  retreats into the bushes.  Silver's arm is dislocated, but West fixes it. Silver asks him if  he's a doctor, but West declines. Silver tells West that the bandits headed for Holysand, the nearest town. When they arrive  in Holysand, they discover a fire in the middle of town set by Silver's stepfather and rancher, Nathan Mitchell. Nathan argues with a rival rancher, Victor Baker about burning the bags of seed that Nathan bought. The argument is broken up by Sheriff Roy Basehart and the local school teacher Denise Stark. Nathan's ranch hand, Garvey orders Silver to clean it up. West walks into the saloon turning everyone's head, because he is new. Instead of ordering  whiskey he orders tea, causing everyone to ridicule him. Garvey offers him a seat and a round  of poker. West wins a hand, but Garvey accuses him of cheating. The sheriff arrests West and  locks him up and Garvey keeps West's money. Later that night Silver tells people about how West  fixed his arm. When the sheriff tells West about his back pain, he suggests getting new boots.  The next morning Nathan's daughter, Millie who West met in the post office,
Output (English): What is the full name of the man that the boy's stepfather is arguing with?