Concept:During the First Republic, the NPC and the NCNC formed the federal ruling coalition, so the main opposition came from the Action Group and its northern ally.
Explanation:After the 1959 federal elections and Nigerian independence, the NPC and the NCNC formed a coalition government.
The Action Group (AG), led by Obafemi Awolowo, took the position of official opposition.
The AG entered an opposition alliance with the United Middle Belt Congress (UMBC) to challenge the federal government.
Therefore, the parties that actually formed the opposition were the AG and the UMBC.
The NCNC was a government partner, not an opposition party in the First Republic.
Answer:Option B: AG and UMBC