The correct answer is option 4, M.N. Roy. M.N. Roy, a prominent Indian political activist and philosopher, proposed the idea of a Constituent Assembly in 1935. He suggested it as a means to draft a constitution for India that would be representative of the people and their aspirations. Although options 1, 2, and 3 were also significant figures in India`s independence movement, they did not propose the idea of a Constituent Assembly in 1935. It is important to note that while M.N. Roy made the initial proposal, it was later taken up by other leaders, including Nehru and Gandhi, who played vital roles in the formation of the Constituent Assembly and the drafting of the Indian Constitution.