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 option reflects the significant trend of pan-Africanism and the desire for unity among African nations and peoples, which characterized many nationalist movements in the postcolonial period. The congress model was often used as a means for different groups to come together to advocate for independence and collective action against colonial powers.