Concept:Internal peace and security in Nigeria is normally the duty of the civil law enforcement agency, not the armed forces.
Explanation:The Nigeria Police Force is the principal law enforcement agency in the country.
Under the Nigerian Constitution, the police are responsible for maintaining law and order, preserving public peace, and protecting the lives and property of citizens.
The army and navy are external defence forces; the army guards the nation's land borders, and the navy secures the maritime domain.
The civil defence corps mainly provides auxiliary services during emergencies and disasters rather than routine internal security.
Therefore, among the options given, the agency that mainly ensures internal peace and security on a day-to-day basis is the police.
Answer:D. police