Concept:The 1963 constitution maintained a federal structure with clear separation of powers.Explanation:The 1963 Republican constitution created an exclusive list of powers reserved for the central authority.These powers included defence, foreign affairs, and major economic matters.This arrangement meant only the central government could legislate on such issues.Regional governments handled subjects like education and health, which were not on the exclusive list.Therefore, the exclusive list belonged to the federal government.Answer:A. Federal government