Concept:A confederal state is a union of independent states that surrender only limited powers to a central body, while retaining sovereignty.Explanation:In a confederal arrangement, member states remain largely self-governing.They cooperate through a weak central authority that exists mainly for common interests.ECOWAS is the best example in the options because its member countries maintain their sovereignty and only cooperate on agreed economic and political matters.Nigeria, Switzerland, and the USA are federal states with strong central governments sharing power with component units.Answer:B. ECOWAS