The correct answer is definitely "a certain sinister block of building", since the word "sinister" immediately creates a sense of disturbance and dread. Then it goes on to describe the building in more details, increasing the claustrophobic sense of the setting in which he's in.
Gothic literature often plays on the sense of wonder and fear that it can generate on the reader both from the contents of the stories as much as the language employed. Utilizing words with gruesome, mysterious or frightening connotations is just as important.
Hope this helps!
Hope this helps!
