Final answer:
Mrs. Kenyon criticizes the narrator for reading a book that likely belongs to a genre for entertainment, such as a mystery or fantasy novel, rather than the literary fiction assigned in class.
Step-by-step explanation:
The book that Mrs. Kenyon criticizes the narrator for reading is not explicitly mentioned in the question. However, using the information provided, we can infer certain details about the nature of the book. Literary classrooms often study literary fiction, including classics by authors such as Dickens, Austen, Twain, and Poe.
As the question suggests that Mrs. Kenyon expected the student to read an assigned book for class, which likely would have been literary fiction, we can deduce that the book the student chose to read instead was not a book usually taught in literature classrooms, and thus likely falls into the category of a genre for entertainment rather than literature.
Therefore, it could have been a mystery novel, a work of fantasy, or another similar genre. Since we do not have the exact title or content of the book, we cannot specify whether it was about a classic novel, a mystery novel, a fantasy novel, or a science textbook without more context.