The response that best analyzes a major pattern in nationalist movements in Africa after 1945 is: There were increased calls for Black African unity and liberation through the congress model.
This statement reflects the significant trend during this period where many African nations sought to unify against colonial powers and promote solidarity among newly independent states. The idea of African unity was a driving force behind various nationalist movements, leading to the formation of organizations like the Organization of African Unity (OAU) in 1963, which aimed to foster cooperation and support for the liberation of remaining colonies.