How does the novel conclude in terms of Buck’s identity?

The correct answer highlights Buck's transformation throughout the narrative. By the conclusion of the novel, Buck has fully embraced his wild instincts, shedding the constraints of domestication. He responds to the calling of the wild, which has been a driving theme throughout the story. This transformation is symbolized when Buck joins a pack of wolves and ultimately rises to become their leader.

In doing so, he not only survives in the harsh wilderness but also finds a new sense of belonging and purpose, marking the completion of his evolution from a domesticated dog to a creature wholly in tune with his primal nature. This journey represents a significant thematic element of the novel, emphasizing the struggle between civilization and the natural world and the instinctual return to one's roots.

The other options would represent a return to a previous life, which contradicts Buck’s journey towards embracing his innate instincts and the wild. Choices involving Buck’s return to civilization or becoming a pet do not align with the arc of his character development as he fully transitions into the wild. Similarly, abandoning his pack does not reflect the conclusion of his identity; instead, he leads and integrates into a pack, showcasing his full acceptance of his identity as a wild creature.