Concept:ECOWAS is a regional organisation that promotes economic and political integration among West African nations.
Explanation:The main advantages of ECOWAS membership include closer economic cooperation among member states.
It also provides access to a larger combined market for goods and labour across the region.
Member countries may receive military assistance through ECOWAS peacekeeping and security initiatives.
However, ECOWAS does not establish or operate free ports for its members as a direct benefit.
Free ports are independent commercial facilities set up by individual governments, not by the regional bloc.
Answer:The correct choice is D. free ports.