Concept:The London Constitutional Conference of 1957 set Nigeria firmly on the path to self-government and eventual independence.
Explanation:At the 1957 London Conference, British officials agreed to grant Nigeria internal self-government.
Nigerian leaders were allowed to control domestic affairs, while Britain retained defence and foreign policy for a short period.
This agreement created the office of Prime Minister and paved the way for Nigeria to assume full political responsibility.
Following later talks, Nigeria finally achieved complete independence on October 1, 1960.
Answer:D. London Conference of 1957