Concept: Identify the regional organization in West Africa that Nigeria helped to establish.Explanation:Nigeria is one of the founding members of the Economic Community of West African States (ECOWAS).ECOWAS is a regional political and economic union created to promote integration and cooperation among West African countries.It was established on May 28, 1975, with Nigeria playing a key role in its formation.Among the options, ECOWAS is the only West African regional organization directly linked to Nigeria's founding membership.Answer: A. ECOWAS