Well, The theme is the moral of the story/lesson taught from the story. So, B isn't a good choice because 1. a wolf was never brought up in the story and 2. that isn't a lesson to be learned. D isn't a good choice because the story doesn't say anything about animals it just talks about Buck and he's exploring nature. So we eliminated B and D so A and C are left. A states that one's true nature will always prevail. Usually this means someones character/personalty changing and his true colors and seeing through. So the story just talks about exploring nature right? So C. Nature is beautiful and powerful would make the most sense since it most relates to the story as a theme. Hope this helps :))
I honestly believe that the answer would be A or C. But, the theme of this excerpt is related more to the 'Nature is beautiful and Powerful' side so I would go with C. Correct me if I am wrong though! I hope this helpful for you though!
Jewish migration into what is now Israel increased after Britain took Palestine from the Ottoman Empire in 1917 and issued a pledge to encourage the "establishment of Palestine as a home for the Jewish people." This pledge is known as the Balfour Declaration.