Answer:
I would go with D
Step-by-step explanation:
Gods and heros do not exist. The events of the story are sort of true, just bent, so its not as true. He did take take 10 years to return home though. Ancient Greece is a real place so that can't be it either. Odysseus being immortal is not even true. In the story he was a mortal.
So, we are left with D, the main characters are gods and heros. :D