Concept:Party alliance is an agreement between two or more political parties to cooperate, usually for elections or forming a government.Explanation:In the Second Republic of Nigeria, the National Party of Nigeria (NPN) and the Nigerian People's Party (NPP) formed a political alliance.This alliance was made on 11th August 1979.The NPN and NPP agreed to support each other in order to strengthen their political positions.The alliance helped them share power at the national level.Answer:B. NPN and NPP.