I would say that the statement which is correct about the differences between short stories and novels is A. an effective short story is carefully crafted to achieve its purpose with fewer words than is a novel.
Novels are usually quite long, and you don't have to limit yourself to any number of words, whereas with short stories, you have to think about how many words you will use, and use them effectively.
The primary function of the sentence "Nature hath made one world and art another" would be that invites the reader to contemplate the nature of reality and art.
