The correct answer is C. Dominant Caste Hindus.
The Zamindari system was a system of land tenure in India in which a small number of landlords, known as zamindars, held large tracts of land and collected revenue from the peasants who worked the land. The system was abolished in 1952, but the social base of land control remained in the grip of the dominant caste Hindus.
The dominant caste Hindus are a group of castes that have traditionally held power in Indian society. They are usually the largest caste in a village or region, and they often have a monopoly on land ownership and political power. The dominant caste Hindus have been able to maintain their power despite the abolition of the Zamindari system by using a variety of methods, including violence, intimidation, and bribery.
The dominance of the dominant caste Hindus has had a number of negative consequences for the lower castes. The lower castes have been denied access to land, education, and employment opportunities. They have also been subjected to discrimination and violence. The dominance of the dominant caste Hindus is a major obstacle to the development of a just and equitable society in India.
The other options are incorrect because they do not represent the dominant caste in Bihar. The middle caste Hindus are a large and diverse group, and they do not have a monopoly on land ownership or political power. The scheduled caste Hindus and the scheduled tribe Hindus are the lowest castes in the Hindu caste system, and they have historically been denied access to land, education, and employment opportunities.