Which best explains the caste system?

a. the belief that the essential self of a living being dies upon reaching nirvana

b. social class division developed by Aryans who believed they were superior to others

c. a set of mental and physical disciplines used to unite the self with the universal essence

B is the one that bests explains the caste system. A caste system is when a society divides people in from birth into a pyramid of social class. The higher the person was on the pyramid the more privilage that person had. Furthermore the people from the class above your class were considered your superiors. In the end, B is the only reliable answer.