Final answer:
The sentence implies that Buck feels superior to other dogs, as they did not seem to matter or challenge his status in 'The Call of the Wild', where survival and adaptability are crucial.
Step-by-step explanation:
The sentence 'There could not but be other dogs on so vast a place, but they did not count' suggests that Buck, the dog in question, likely feels a sense of superiority towards other dogs. Buck's feelings are not explicitly mentioned as jealousy, isolation, or feeling mistreated, which rules out the other options provided. In the context of Jack London's 'The Call of the Wild', Buck, a once domesticated dog that is sold to become a sled dog, has to adapt to a harsh environment. This adaptation and survival of the fittest mentality contribute to Buck's feeling of superiority amongst other dogs who may not be as capable in such an environment.