Concept:The highest judicial authority for Nigeria before it became a republic was the British Privy Council.Explanation:Before Nigeria became a republic in 1963, its court system allowed final appeals to the Judicial Committee of the Privy Council in Britain.This means judgments from Nigerian courts, including the Supreme Court, could be reviewed by the Privy Council.Therefore, the Privy Council, listed as the Privy Court in the options, was the supreme body for justice administration.Answer:C. Privy Court