Concept:Identifying the international event hosted in Lagos in 1973 under General Yakubu Gowon.Explanation:In 1973, Nigeria successfully hosted the second All-Africa Games in Lagos.Gowon officially opened the games, which drew athletes from many African nations.This event showcased Nigeria’s organisational capacity and sporting development.It is widely recognised as a major achievement of his administration.The OAU Summit, Non-Aligned Movement Conference, and Commonwealth Heads of Government Meeting were not held in Lagos in 1973.Answer:A. The All-Africa Games