Correct Answer: (c) Udhamsingh Nagar
Solution:According to Census 2011, total population of Scheduled Tribes in Uttarakhand was 291,903. Two scheduled Tribes majority districts of Uttarakhand are Udham Singh Nagar and Dehradun. Udham Singh Nagar had the maximum Scheduled Tribe population (1,23,037) followed by Dehradun (1,11,663).