The answer is Textbook, I believe
I would say the correct answer is B. primitive man.
The point of the entire novel is that Buck is fighting his urges to go to the wilderness and succumb to his wild identity of a wolf. Thus, dreaming about the primitive man clearly portrays his struggle between his two identities, that of a domesticated dog and that of a wild wolf.
The correct answer is long-term
Short term would be something like passing the exam with a high mark, while management would be on devising a plan on how to manage your time. An impossible would be if you planned to do it without even being enrolled in the school.