The correct answer is: A. Sheohar
Sheohar district has the lowest Scheduled Caste population in Bihar, with only 12.2% of the total population belonging to this group. This is significantly lower than the state average of 16.3%.
The other options are incorrect because they have a higher Scheduled Caste population than Sheohar. Gaya district has a Scheduled Caste population of 16.9%, Patna district has a Scheduled Caste population of 17.4%, and Kishanganj district has a Scheduled Caste population of 18.1%.
The Scheduled Castes are a group of people who have been historically discriminated against in India. They are listed in the Constitution of India as being socially and educationally backward. The government of India has implemented a number of affirmative action policies to improve the social and economic status of the Scheduled Castes.