Concept:Before the OAU was formed, African states were divided into ideological blocs based on their approach to continental unity.Explanation:The Monrovia Group was a moderate bloc of African states that supported gradual and peaceful unity.Nigeria was a founding member of the Monrovia Group, which included countries like Liberia and Sierra Leone.The Casablanca Group was the more radical bloc led by Ghana, while the Brazzaville Group was largely Francophone.At the formation of the OAU in 1963, Nigeria identified with the Monrovia Group.Answer:A. Monrovia Group