Answer:
The correct answer is B. Human beings often need the help of animals in order to live.
Step-by-step explanation:
All the options are valid, however, A, C and D are extracts from the story, not really coming off as the central idea of the story.
B provides a complete answer since at the end it turns out Aaron survived thanks to Zlateh and its milk, otherwise he would've died in the blizzard.
In this case, it can be concluded that humans often need animals' help which we can see in daily life. Animals can provide food filled with nutrients such as eggs and milk, as well as fur and even protection, such as guard dogs.