What is Ismene's relationship to Antigone?

Ismene's relationship to Antigone is that they are sisters. In the play "Antigone" by Sophocles, both characters are daughters of Oedipus and Jocasta, making them siblings. This familial bond is central to the plot and themes of the play, particularly in terms of loyalty, duty, and the conflict between individual morals and state laws. Their different approaches to the law and their roles within the family highlight the complexities of their relationship as sisters. The other options confuse the nature of their familial ties; they are not cousins, daughters of anyone other than Oedipus and Jocasta, nor merely friends.