Answer: D) By referring to the lighting-rod man as Mr. Jupiter Tonans, a pagan god, the narrator is calling the salesman a pagan as well.
Step-by-step explanation: allusion is a literary device that consists in making a brief reference to a person, an event (historical, political, cultural, etc), or a place. In the given excerpt from "The Lightning-Rod Man" by Herman Melville, we can see an example of an allusion to the god Jupiter Tonans, with this allusion, the narrator is calling the salesman a pagan, so the correct answer is option D.