Nigeria was granted independence on October 1, 1960. A new constitution established a federal system with an elected prime minister and a ceremonial head of state. The NCNC, now headed by Azikiwe (who had taken control after Macaulay’s death in 1946), formed a coalition with Balewa’s NPC after neither party won a majority in the 1959 elections. Balewa continued to serve as the prime minister, a position he had held since 1957, while Azikiwe took the largely ceremonial position of president of the Senate. Following a UN-supervised referendum, the northern part of the Trust Territory of the Cameroons joined the Northern region in June 1961, while in October the Southern Cameroons united with Cameroun to form the Federal Republic of Cameroon. On October 1, 1963, Nigeria became a republic. Azikiwe became president of the country, although as prime minister Balewa was still more powerful.
I'm sure the answers d, because it would help way more than the other options you'd want to know first hand what happen the only way to do so is to speak to those who fought in the war.
