What emotion best describes Buck's feelings towards the work under the mail carriers? rage defeat passion pride

In "The Call of the Wild", by Jack London, the emotion that best describes Bucks's feelings towards the work under the mail carriers is pride. When Buck is sold to two French Canadian men, Francois and Perrault. He learns how to deal with wilderness and snow. He soon becomes the lead dog. With him in the front they make a record time. He is very proud, and enjoys his life.