Answer:
(C)
Step-by-step explanation:
Oedipus and Jocasta have four children, two boys and two girls; Oedipus's children are also his half-siblings. Obviously this is a horrific truth, and of course neither Jocasta not Oedipus would have been in this relationship if they had known the truth. In Oedipus Rex by Sophocles, this truth is not revealed until the end of the play.