Read this excerpt from The Call of the Wild by Jack London. Buck had accepted the rope with quiet dignity. To be sure, it was an unwonted performance: but he had learned to trust in men he knew, and to give them credit for a wisdom that outreached his own. But when the ends of the rope were placed in the stranger's hands, he growled menacingly. He had merely intimated his displeasure, in his pride believing that to intimate was to command. But to his surprise the rope tightened around his neck, shutting off his breath.

What theme does the excerpt convey?

It is right to be wary of the unknown.
Pride interferes with progress.
Manners must be displayed in all situations.
Strange animals cannot be trusted.