The correct option is B 15 February 1948
On 15 February 1948, the Bhavnagar state was merged with United Saurashtra state. In November 1948, the United State of Kathiawar was renamed the United State of Saurashtra. Bhavnagar State was a princely states during the British Raj. It was part of Kathiawar Agency in Saurashtra. Saurashtra State was a separate state within the Union of India, which existed from 1948 to 1956. It was formerly known as United State of Kathiawar.