In the fourth episode, the Servant actually eagerly answers to Oedipus's questioning about his heritage - that he was abandoned by his parents and that he is that same baby he had been asking around about.
Answer: D, because the articles talk about this specific answer and it provides text evidence in the text to this answer.
The answer is D because if you should learn more about the topics to see if that is what you want to do. It is always good to have more than just one topic.
