Answer:
The best option about the dog's change in the story is:
C. At the beginning of the story, the dog is afraid of Gordon Low; by the end, the dog is loyal to him.
Step-by-step explanation:
"[...] he seemed no longer to fear the man who had raised him from the bog. That night he followed Gordon Low to his door. [...] until the dog himself died [...] he loved Gordon Low as once he had loved the lonely trapper of Caucomgomoc."
Loyal to his owner, the trapper, the dog refuses to be taken by any other humans. Gordon Low does try to feed and take care of the dog once the trapper dies, but the hound chooses to escape into the wilderness. Years later, however, the dog saves Gordon Low's grandson and is, in his turn, saved by Gordon Low. This is how he finally learns to trust and love this man, choosing to be domesticated again instead of living in the forest.