The Cabinet Mission was a delegation sent by the British government to India in 1946 to discuss and negotiate the terms of India`s independence. The question asks about the person who was not a member of the Cabinet Mission.

Option 1: Sir Stafford Cripps

Sir Stafford Cripps was a British statesman who served as the leader of the mission. He was a member of the Cabinet Mission.

Option 2: A. V. Alexander

A. V. Alexander, also known as Lord Alexander, was a British politician and a member of the Cabinet Mission. He played a crucial role in the negotiations.

Option 3: Radcliffe

Radcliffe was not a member of the Cabinet Mission. He was a British lawyer who was later appointed to head the boundary commission to demarcate the borders between India and Pakistan.

Option 4: Pethwick Lawrence

Pethwick Lawrence was a British politician and a member of the Cabinet Mission. He was one of the three members of the mission who were sent to India.

In conclusion, among the given options, Radcliffe was not a member of the Cabinet Mission.