The correct answer is: A. 320
Article 320 of the Indian Constitution defines the functions of Public Service Commission. It states that there shall be a Public Service Commission for the Union and for each State. The Commissions shall be constituted by the President and shall consist of a Chairman and such number of other members, not exceeding six, as the President may deem fit. The Chairman and members of a Public Service Commission shall be appointed by the President on the recommendation of a committee consisting of the Prime Minister, the Home Minister, and the Leader of the Opposition in the House of the People.
The functions of a Public Service Commission are to conduct examinations for appointments to the services of the Union and the State; to advise on matters relating to methods of recruitment to civil services and posts; to advise on the suitability of candidates for appointment to civil services and posts; and to inquire into complaints against civil servants.
The Public Service Commissions are independent bodies and are not subject to the control of the Government. They are responsible to the Parliament and the State Legislatures.