Who were supporters of Quit India movement?

Context: The Quit India Movement, also known as the Bharat Chhodo Andolan, was a movement launched at the Bombay session of the All India Congress Committee by Mahatma Gandhi on 8th August 1942, during World War II, demanding an end to British rule in India.

After the British failed to secure Indian support for the British war effort with Cripps Mission, Gandhi made a call to Do or Die in his Quit India movement delivered in Bombay on 8 August 1942 at the Gowalia Tank Maidan. Viceroy Linlithgow remarked the movement to be "by far the most serious rebellion since 1857".

The All India Congress Committee launched a mass protest demanding what Gandhi called "An Orderly British Withdrawal" from India. Even though it was at war, the British were prepared to act. Almost the entire leadership of the Indian National Congress was imprisoned without trial within hours of Gandhi's speech. Most spent the rest of the war in prison and out of contact with the masses. The British had the support of the Viceroy's Council, of the All India Muslim League, the Hindu Mahasabha, the princely states, the Indian Imperial Police, the British Indian Army, and the Indian Civil Service. Many Indian businessmen profiting from heavy wartime spending did not support the Quit India Movement. The major outside support came from the Americans, as President Franklin D. Roosevelt pressured Prime Minister Winston Churchill to give in to some of the Indian demands.

Various violent incidents took place around the country against the British regime. The British arrested tens of thousands of leaders, keeping them imprisoned until 1945. Ultimately, the British government realised that India was ungovernable in the long run, and the question for the postwar era became how to exit gracefully and peacefully.

Answer: Indian National Congress
American president Franklin D Roosevelt