For Part A, the best explanation for why Oedipus insists that he has done the right thing by putting out his eyes is:
B. He believes he must atone for his crimes before he dies.
Oedipus feels a deep sense of guilt and responsibility for his actions, particularly regarding the crimes he committed without knowing their true nature.
For Part B, the line of dialogue that best supports the answer to Part A is:
A. Oedipus. I have sinned against them both. To hang myself would not wash clean that sin.
This statement directly reflects Oedipus's belief in the need for atonement and the weight of his guilt, reinforcing the idea that he feels the need to confront his actions rather than escape them.