C. Many African and Asian nations are based on former colonial boundaries.
Explanation:
The European imperialism managed to have impact on much of the world. The Americas, Africa, Asia, Australia, Oceania were all heavily impacted. While some former colonies managed to fully move away and almost have no trace that they were colonies, many still have bad consequences from it.
One of those traces and consequences are the boundaries. The majority of the African countries and some countries in Asia still have the colonial boundaries. While this may not seem as a problem it is actually a very big one. The reason as to why this is problem is that people from different religious, ethnic, and linguistic groups have been put in the same borders. Lot of these groups traditionally have bad blood between them and don't tolerate each other.
This situation in many cases has resulted in internal division of the countries. Multiple civil wars have occurred and even genocides. The tensions still persist to this day and unfortunately don't seem like they will be calmed down anytime soon.