Concept:The National Defence Council advises the President on defending Nigeria's sovereignty and territorial integrity.
Explanation:The 1999 Constitution of Nigeria establishes the National Defence Council.
Its main function is to advise the President on matters concerning the defence of Nigeria's sovereignty and territorial integrity.
This includes protecting the nation's land, sea, and air borders from external aggression.
The National Security Council, in contrast, advises the President on public security and internal security threats.
The Council of State advises on broad policy issues and national stability, not specifically on territorial defence.
The Federal Executive Council is the cabinet and handles the general administration of the country.
Only the National Defence Council is charged with the specific duty described in the question.
Answer:A. National Defence Council