Answer:
A. The dangers of arrogance
Step-by-step explanation:
Their arrogance is what led Oedipus to kill the stranger/ his father, so it makes sense that this would be the answer. Words such as "insolent" also support this conclusion because insolent means "showing a rude and arrogant lack of respect."
But just to confirm let's use process of elimination and take a look at the other ones
B. Physical transformation -- no one and no thing is changing their physical form
C. Explanations of nature -- there is no theme of natural events or any sort of interaction with nature
D. The hero's journey -- one could argue that this could be a step of the hero's journey but not to describe this one event
Hope this helps!