Concept:The Lyttleton Constitution of 1954 is significant because it introduced the federal system of government in Nigeria.Explanation:The 1954 constitution was named after Oliver Lyttleton, the Secretary of State for the Colonies.It created a federal structure by dividing Nigeria into regions, each with its own regional government.A central government was also established to handle national matters.This marked the official shift from a unitary system to federalism in Nigeria.Answer:A. introduced the Federal system of government.