The correct answer is (c) 1948.
The Tehri Kingdom was a princely state in India that existed from 1803 to 1948. It was located in the Garhwal Himalayas, in the present-day Indian state of Uttarakhand. The kingdom was founded by Maharaja Pratap Shah, who was a descendant of the Chand dynasty of Garhwal.
In 1947, India gained independence from British rule. The Tehri Kingdom was one of the 562 princely states that existed in India at the time. The rulers of these states were given the choice of joining either India or Pakistan. The Maharaja of Tehri, Sriman Chand Pratap Shah, decided to join India.
The Tehri Kingdom was merged with the Indian Union on 15 May 1948. The Maharaja was given a privy purse and a title of Rajpramukh. The kingdom was reorganized into the Tehri Garhwal district of the United Provinces (now Uttar Pradesh).
The options (a), (b), and (d) are incorrect because they are not the years in which the Tehri Kingdom was merged with the Indian Union.