The correct answer is: b) Gaonburas.
Gaonburas are hereditary chiefs in some tribal societies in Arunachal Pradesh. They are responsible for the administration of their villages and for settling disputes between their people. They are also the leaders of their people in times of war.
Zamindars were hereditary landlords in India who collected taxes from the peasants who lived on their land. Posa are a type of traditional dance performed by the Apatani people of Arunachal Pradesh. Rajas are kings or rulers in India.
Gaonburas are an important part of the social and political structure of many tribal societies in Arunachal Pradesh. They play a vital role in maintaining order and stability in their communities.