What Is the Mission of the Organization of African Unity

What is the mission of the Organization of African Unity (OAU) ?

A) It is a free trade association, like NAFTA and the EU.
B) Its primary purpose is to develop Africa-wide environmental policy.
C) Its objective is to fight international terrorism in Africa.
D) Like the U.S. Peace Corps, its mission is to promote economic development.
E) Its function is to mediate disputes between African countries.