The correct answer is Bhavnagar.
The ruler of Bhavnagar, Maharaja Jaswantsinhji, signed the Instrument of Accession on 5 July 1947, making Bhavnagar the first princely state in India to accede to the Dominion of India.
Baroda, Nawanagar, and Wankaner were all princely states in India that acceded to the Dominion of India after Bhavnagar. Baroda acceded on 15 August 1947, Nawanagar acceded on 18 August 1947, and Wankaner acceded on 20 August 1947.
The Instrument of Accession was a document signed by the rulers of the princely states of India in 1947, in which they agreed to accede to the Dominion of India. The Instrument of Accession gave the Dominion of India control over the princely states’ foreign affairs, defense, and communications, while the princely states retained control over their internal affairs.
The Instrument of Accession was a key step in the process of Indian independence. It allowed the Dominion of India to inherit the princely states’ territory and resources, and it helped to ensure that the transition to independence was peaceful.