Answer:
A. an extraterrestrial or alien race
Step-by-step explanation:
According to the given excerpt, the author describes the Tasmanians - who are described to have a human likeness - and Martians who were more advanced than humans. These two races are not described as humans, so they are an extraterrestrial or alien race.
Therefore, the details that help classify this story as science fiction is the mention of an extraterrestrial or alien race.