Which of the following had a centralized administration in pre-colonial Nigeria?

The Yorubas had a centralized administration in pre-colonial Nigeria. The Yoruba people were organized into various city-states, each with a centralized system of government. The system of government in Yoruba city-states was a monarchy, with a king or "Oba" at the head of each state. The Oba had authority over the various chiefs and councils that made up the government, and he was responsible for maintaining law and order, collecting taxes, and defending the state against external threats. The Yoruba system of government was highly organized and efficient, with a well-defined hierarchy of authority, and it remained intact until the advent of colonialism in the late 19th century.