The correct answer is A) Pattom Thanu Pillai.
Pattom Thanu Pillai was a prominent Indian politician and social reformer who played a major role in the unification of the princely state of Travancore with the Malabar district of British India. He was the leader of the Aikya Kerala (United Kerala) movement, which campaigned for the unification of the two regions.
T.M. Varghese was a social reformer and politician who was also a member of the Aikya Kerala movement. However, he was not the leader of the movement.
K.M. Panikkar was a historian and diplomat who was also a member of the Aikya Kerala movement. However, he was not the leader of the movement.
Fazal Ali was a politician and statesman who was the Chief Minister of the United Provinces from 1937 to 1939. He was not a member of the Aikya Kerala movement.