Concept:The African Union (AU) was created to replace the Organisation of African Unity (OAU) with a stronger mandate and greater institutional capacity to act on continental issues.
Explanation:The OAU was founded mainly to promote decolonisation and defend the sovereignty of newly independent African states.
It operated on strict non-interference and lacked practical authority to enforce its decisions on member states.
The AU, on the other hand, was designed as a more integrated body with a wider vision of unity and development.
Unlike the OAU, the AU has working institutions such as the Peace and Security Council and the African Standby Force.
These organs give the AU effective tools to enforce decisions, mediate conflicts, and intervene when necessary.
Therefore, the key difference between the AU and the OAU is the AU's possession of effective enforcement mechanisms rather than just advisory or declaratory powers.
Answer:A. Effective tools for decision enforcement