Correct Answer: (a) 21 August, 1949
Solution:Tehri Praja Mandal was formed in 1939 in Dehradun (in Present Uttarakhand). With the establishment of Tehri Praja Mandal' in the leadership of Deo Suman, the movement for rights of the people intensified. He went on a hunger strike for 84 days in the prison. Deo Suman also fought against the dynastic rule in Tehri state and gave thrust to the process of integration of Tehri state with the Indian Union. As a result, Tehri became a district of the then Uttar Pradesh on 1 August, 1949.