(from The Strange Case of Dr. Jekyll and Mr. Hyde, by Robert Louis Stevenson) Read the passage carefully and then answer the question.

Two doors from one corner, on the left hand going east the line was broken by the entry of a court; and just at that point a certain sinister block of building thrust forward its gable on the street. It was two storeys high; showed no window, nothing but a door on the lower storey and a blind forehead of discoloured wall on the upper; and bore in every feature, the marks of prolonged and sordid negligence. The door, which was equipped with neither bell nor knocker, was blistered and distained. Tramps slouched into the recess and struck matches on the panels; children kept shop upon the steps; the schoolboy had tried his knife on the mouldings; and for close on a generation, no one had appeared to drive away these random visitors or to repair their ravages.

Mr. Enfield and the lawyer were on the other side of the by-street; but when they came abreast of the entry, the former lifted up his cane and pointed.

"Did you ever remark that door?" he asked; and when his companion had replied in the affirmative. "It is connected in my mind," added he, "with a very odd story."

"Indeed?" said Mr. Utterson, with a slight change of voice, "and what was that?"

The word in bold is an example of what kind of tone?

A. uninviting.

B. confusing.

C. exciting.

D. thrilling.