The answer is: The pacing slows down the text with deliberate and descriptive language, which gives the story a mysterious atmosphere.
In the excerpt from "After Twenty Years," the author O. Henry describes the winter scene with details about the weather and the how the people in the street are behaving, which gives a sense of mystery to the story.
The rest of the options are incorrect because the events in the passage do not depict surprise, humor or alarm. Besides, there is no further description of the man, and the pacing is not fast.
