Final answer:
The archetype that best fits the description is the Mysterious stranger.
Step-by-step explanation:
The archetype that best fits the description of the lone rider who comes into town asking odd questions about the water supply is the Mysterious stranger. This archetype is commonly found in literature and movies, where a character enters a new setting and acts in a strange or mysterious way, arousing curiosity and creating an aura of intrigue around themselves.
Learn more about Archetypes in Literature