The social hierarchy that was established in china by the mongols

a. kept the chinese people separate from the mongols.
b. brought the chinese people and the mongols together.
c. kept the rural areas separate from the urban areas.
d. brought the rural areas and the urban areas together.

The answer would be letter A.  Kept the Chinese people separate from the Mongols.   The four classes separated the different kinds of Chinese and Mongols in China. The first class is composed of the Mongolians. The second class is composed by the Semu people. The third and fourth classes are the Han dynasty and Northern Songs dynasty. Each class has its own benefits. There is an unequal treatment for each class. The Manchu dynasty has a strict policy that will give them dominance over the Mongolian Empire.