Answer:
Option A. The two characters in The Sweet Hereafter who are flat characters are Sean Walker and Bear Otto.
Step-by-step explanation:
Written by Russel Banks in 1991, "The Sweet Hereafter" is a dramatic novel that tells the story of a fatal school bus accident and its aftermath through four first-person narrators. The characters of Sean Walker and Bear Otto can be considered to be flat as they are both kids that lose their lives in the accident, therefore their characters do not develop through the story line.
In literature, a flat character is two-dimensional in that he/she is not complicated and do not change throughout the story.