Answer:
A.
Step-by-step explanation:
First of all, this question is out of context. Second, the answer is a. Oedipus didn't know that the king of a nation was his father and the queen was his mother. When he killed the king to take over, he married the queen without knowing that it was his mother.
Credit Annabelle Peeler for telling me about Oedipus a couple weeks before this question.