The Nigerian civil war lasted _____ months.

The Nigerian civil war, also known as the Biafran war, lasted for 30 months. The war was fought between the government of Nigeria and the secessionist state of Biafra, which was located in the southeast of Nigeria. The war began on July 6, 1967, when Biafra declared its independence from Nigeria, and it ended on January 15, 1970, when Biafran forces surrendered to the Nigerian government. The war was a result of ethnic tensions and political disagreements between the Igbo people, who dominated the southeast, and other ethnic groups in Nigeria. The conflict was characterized by a blockade of Biafra, which caused widespread famine and led to the deaths of many people. Therefore, out of the options given, the correct answer is "30."