Most caste systems in our history were based on a person's skin color. I'm gonna take a guess that it would be the same for this part of the world.
While you didn't really provide the "following" as the comment above me states, in general, the advantage of secondary sources of primary ones is that they perhaps provide a more objective or even just a broader view on a certain topic. While a primary source of the American civil war would be a letter written by a soldier, a secondary source would be a book that describes more letters taken together and discusses possible information regarding them.
Great Britain should be teh answer xD
Hope This Helps ☺
I’m pretty sure it’s c. If it’s wrong I’m sorry! Have a great day.
