What emotion does Buck primarily feel toward his owners?

Buck's primary emotion toward his owners is respect, particularly towards those who demonstrate strength and skill in their roles. Throughout "The Call of the Wild," Buck evolves from a domesticated pet to a creature in tune with his instincts. His respect emerges in relation to John Thornton, who treats Buck with kindness and recognizes his abilities. This bond signifies a mutual understanding and admiration, illustrating how Buck responds positively to those who treat him well and understand his needs as both a dog and a living being.

Other emotions like fear, disdain, or apathy might occasionally surface, especially in response to harsh treatment by other owners, but they do not encapsulate Buck's overall relationship with those who gain his respect. The connection he forms with Thornton exemplifies a deeper appreciation that goes beyond mere obedience; it reflects a loyalty and recognition of shared values and experiences. Thus, respect is the most accurate representation of Buck's feelings toward his rightful owners in the story.