The people and how it is managed
This statement would be more or less correct I would say.
Nationalism inded did develop strongly in the 19th century, and also in a lot of cases led into the development of nation states. At the same time, powerful empires that existed in those times had often many different ethnic and political groups in their borders. All of these factors often led to different wars that were quite horrible.
The answer would be C. the nobles who lived in luxury
Muslims invaded North Africa and occupied those territories and imposed jizya on the people. After a while the Non-Muslims were sick of being oppressed by the invaders and decided to become Muslims so that the burden of an extra tax would be removed.
