Option a. the beginning of a story, when the characters are introduced
Exposition is the insertion of the important background within a story. It is the process of scattering information through the text. Incluing is a technique in which the reader is gradually exposed to background information about the world in which the story is set. The idea is to clue the readers into the world the author is building them without being aware of it.
"The water rises and the band plays ragtime", and "Stewards finish waking their passengers below; life preservers are tied on; some men smile at the precaution"
Explanation:
Options A and D are correct, I hope this helps you :)