Answer : b. four
The caste system in India is a system in the society which classifies people into occupational groups. The system is ranked based on a hierarchy. It is made up of four classes, the Brahmana, Kshatriya, Vaishya, and the Shudra. The class of Brahmana is made up of people who are involved in the teaching of the scriptures. Kshatriya are those people who are in the public service while Vaishya are made up of those people in the commerce like businessmen. On the other hand, Shudra are those unskilled or semi-skilled workers.