Did you mean to include a link to a story? :)
Answer: The purpose of an excerpt is to be a trailer for a book.
Explanation: A excerpt can be like a little sneak peak that prepares the reader for the whole story. An excerpt can also help the the reader understand and memorize the subject the author is writing about.
What I am confused where is the question
I think 1 is either A or D & 2 is either A or B. I hope I helped & I'm sorry if I'm wrong :)