The formula for transfer of sovereignty to India in 1947 was known as :

Durand Plan
Morely-Minto Reforms
Mountbatten Plan
Wavell Plan

The correct answer is (c).

The Mountbatten Plan was a proposal to transfer power from British India to two independent dominions, India and Pakistan. It was announced on June 3, 1947, by Lord Mountbatten, the last Viceroy of India. The plan was accepted by the Indian National Congress and the Muslim League, and it was implemented on August 15, 1947.

The Durand Plan was a treaty signed in 1893 between the British government and the Amir of Afghanistan, Abdur Rahman Khan. The treaty defined the border between British India and Afghanistan.

The Morley-Minto Reforms were a series of reforms introduced in British India in 1909. The reforms introduced a system of dyarchy, in which some subjects were administered by the British government and others were administered by Indian ministers responsible to an elected legislative council.

The Wavell Plan was a proposal to transfer power from British India to a single dominion. It was announced on May 16, 1946, by Lord Wavell, the Viceroy of India. The plan was rejected by the Indian National Congress and the Muslim League, and it was not implemented.