Final answer:
While styles like nostalgic, suspenseful, humorous, or hopeful can all be effective in children's literature, there isn't one definitive style that should never be used. The appropriateness of each depends on the story's context and the author's intent.
Step-by-step explanation:
Content in a book for children should NOT be treated in a style that is nostalgic, suspenseful, humorous, or hopeful for the future. While all of these styles can be effective in children's literature, the question is subjective and the appropriateness of each style depends on the context of the story and the message the author wishes to convey. It's important to note that each style has its place and can be used successfully in children's books. Nostalgia can help relate past experiences to present ones; suspense can keep readers engaged; humor can make reading enjoyable and relatable; and hope can inspire and positively influence young readers. Therefore, there isn't a definitive style that should never be used in children's books; what matters most is how the content is handled to suit the intended audience.