Final answer:
The reason not many people stay at the bed and breakfast in 'The Landlady' is not specified within the story, contributing to its mystery and suspense.
Step-by-step explanation:
The reason why many people don't stay at the bed and breakfast in the story "The Landlady" by Roald Dahl is D) Not specified in the story. The narrative focusses on the experiences of the protagonist, Billy Weaver, and the peculiar characteristics of the landlady and her establishment.
The absence of other guests and any explicit reasons for this are not provided in the text, thus contributing to the mysterious and suspenseful atmosphere of the story.