Detailed Solution:
The correct answer is “Mountbatten Plan”.
The formula for transferring sovereignty to India in 1947 was called the Mountbatten Plan, also known as the 3rd June Plan. The British government announced the plan on June 3, 1947, and the British Parliament passed the Indian Independence Act based on the plan on July 18, 1947.
The transfer of power took place at midnight on August 14–15, 1947.