The correct option is A Four
Varna system started in Vedic Period. It finds mention in Rig Veda and Manusmriti. It is basically classification of people based on their occupation or position they hold in society according to which society is divided into four classes viz., Brahmans (priests or scholars having high position) , Kshatriyas (Warriors or knights), Vaishyas (traders), Shudras (unskilled workers or labourers). Varna in RigVeda means colour, complexion or outward experience. Varna system did not classify people as high and low or superior or inferior it was just classification in the order of the society based on the skills of people. The Varna system took form of caste system where people were stratified as high or low and Swarnas (upper two Varna's) imposed their system.