Correct Answer: (a) Oraon
Solution:A social institution called 'Dhumkuria' belongs to the Oraon tribe. It is an Adivasi Group inhabiting various states across central and eastern India. Dhumkuria provided training in socio-cultural, politico-economic and religious grounds, as well as mores of collective living. It encouraged learning by doing, as well as teaching while learning β to younger and from elder cohorts, simultaneously.