The correct answer is: Chief Minister.
The Chief Minister is the head of the state executive in Tamil Nadu. The Chief Minister is appointed by the Governor of Tamil Nadu, who is the head of state. The Chief Minister is the leader of the party or coalition that has the most seats in the Tamil Nadu Legislative Assembly. The Chief Minister is responsible for the day-to-day running of the state government.
The Governor is the head of state in Tamil Nadu. The Governor is appointed by the President of India. The Governor is the representative of the central government in the state. The Governor has the power to dissolve the Legislative Assembly, to appoint the Chief Minister, and to give assent to laws passed by the Legislative Assembly.
The President is the head of state of India. The President is elected by an electoral college consisting of members of both houses of Parliament and the legislative assemblies of the states. The President has the power to appoint the Prime Minister, to dissolve the Lok Sabha, and to give assent to laws passed by Parliament.
The Chief Secretary is the chief administrative officer of the state government. The Chief Secretary is appointed by the Governor on the advice of the Chief Minister. The Chief Secretary is responsible for the day-to-day running of the state administration.