Answer: A) Allusion.
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 Apology" when Socrates uses the word "Herculean" he is making an allusion to "Hercules" who was a Roman hero and god, son of Zeus (in the Greek mythology) and who was famous for his great strength and endurance.