The question asks about the person who was not a member of the Drafting Committee of the Constitution of India. The correct answer is option 4, M. K. Gandhi.

Option 1, B. R. Ambedkar, was indeed a member of the Drafting Committee. He played a crucial role in the drafting and framing of the Indian Constitution, and is often referred to as the principal architect of the constitution.

Option 2, K. M. Munshi, was also a member of the Drafting Committee. He was a lawyer, writer, and politician who made significant contributions to the drafting process.

Option 3, Krishnaswamy Iyer, was another member of the Drafting Committee. He was a distinguished lawyer and legal expert who contributed his expertise to the drafting and formulation of the constitution.

Therefore, the correct answer is option 4, as M. K. Gandhi, although an influential figure in the Indian independence movement, did not serve on the Drafting Committee.