From what I saw when looking for the answer, we want what is explicitly stated. Now you are correct with your understanding of the question. However, what sets the answers apart is that it is LESS frightening compared to the characters either being in the story or almost not at all. If it was about Yoko only I could see B being right. But we want to know what they BOTH disagree over. D would be correct since it is about stories having or not having immoral characters. Another way to see the answer is by seeing the statement"clearly having immoral characters" in both statements. Hopefully, this can clear up any confusion.