Answer:
B. colonial powers lumped and separated indigenous groups into arbitrary countries.
Explanation:
Postcolonial countries of Africa were formed during the independence around 1963, but there was an agreement that the Organization of African Union could not violate the colonial’s boundaries set before.
Because of that agreement after the decolonization some countries changed their names but they kept the division made in Berlin Conference of Africa (1884), which divided it in fifty countries, which were still under colonial powers. In the division they did not consider cultural differences, language or tried to keep the same tribes in the same country, it was a separation of indigenous groups into arbitrary countries.