Concept: Nigeria’s membership of ECOWAS is rooted in the goal of regional economic cooperation and unity.
Explanation: The Economic Community of West African States (ECOWAS) was formed mainly to promote economic integration among West African countries.
As a founding member, Nigeria joined to encourage free trade, remove trade barriers, and support the free movement of people and goods within the sub-region.
This desire is directly linked to economic rather than military or political ambitions.
While a market may develop in the sub-region, that is only a result of integration, not the primary motive.
Similarly, forming a sub-regional high command or seeking to become a sub-regional power does not reflect the central aim of Nigeria’s membership.
Therefore, the best answer is the promotion of economic integration.
Answer: D. promote economic integration