The Difference Between Public International Law and Private International Law

The difference between public international law and private international law is that

A) private international law is made in international conferences whereas public international law is only made by agreement.
B) there is no real difference. Both apply to the same things.
C) public international law is made in public while private international law is made "in private", ie secretly.
D) public international law concerns relations between states whereas private international law is the domestic law of a country that a court in that country applies to determine what domestic law applies to a private transaction that has elements related to more than one jurisdiction.
E) none of the above