Read the excerpt from The Call of the Wild.The team of ten dogs was unhitched, and Buck, with his own harness, was put into the sled. He had caught the contagion of the excitement, and he felt that in some way he must do a great thing for John Thornton.

Buck is excited and feels he must do something great for John Thornton, showing his devotion and eagerness to serve him. This best matches “Buck’s obedience to serve Thornton.” The excerpt focuses on Buck’s bond with Thornton, not survival, returning to the wild, or distrust of people.

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