The correct option is D All of above
The rise of middle class- All colonial power established their educational institutions to give education and to make use of them for administration. From this knowledge they came to know about their critical conditions of economic exploitation, poverty and slavery system.
The rise of Nationalism- The spirit of nationalism was imbibed in African colonies. They began to think about freedom, Thus National movement were raised in the colonies.
National movement- National movement in 1957 was started in all African regions for freedom.