Answer:
B. Mr. Nuttel is a weak character and is therefore easily misled by all of the characters, creating a conflict between appearance and reality.
Step-by-step explanation:
Remember, in the story, we are told that Mr. Nuttel was undergoing treatment for a “nerve cure,” which could imply that he is a weak character. This weakness of his makes him easily misled and easily frightened by all of the characters.
For example, he wasn't only deceived by Vera’s story but was also frightened by Mrs. Sappleton's remarks.