The correct answer is: a) Ministry of Tribal Affairs.
The Ministry of Tribal Affairs is the nodal ministry of the Government of India for the welfare of Scheduled Tribes. It was established in 1950 as the Ministry of Tribal Welfare. The ministry is responsible for the implementation of various schemes and programmes for the development of Scheduled Tribes. It also provides financial assistance to states and union territories for the welfare of Scheduled Tribes.
The Ministry of Social Justice and Empowerment is responsible for the welfare of all socially disadvantaged groups, including Scheduled Tribes. It implements various schemes and programmes for the education, health, employment, and housing of Scheduled Tribes.
The Ministry of Rural Development is responsible for the development of rural areas. It implements various schemes and programmes for the improvement of agriculture, irrigation, rural roads, drinking water, and sanitation in rural areas.
The Ministry of Home Affairs is responsible for the maintenance of internal security and law and order. It also deals with issues related to refugees, foreigners, and border management.
The Ministry of Tribal Affairs is the most appropriate ministry to work for the welfare of Scheduled Tribes as it is specifically mandated to do so. The other ministries also have some role to play in the welfare of Scheduled Tribes, but their role is not as significant as that of the Ministry of Tribal Affairs.