Correct Answer: Reserve Bank of India (RBI)

Solution : The correct answer is (a). Reserve Bank of India (RBI) 

The Reserve Bank of India (RBI) is the central bank of India and is responsible for the regulation and supervision of the banking sector in the country. It is the primary authority that oversees the functioning, operations, and policies of commercial banks, including both public and private sector banks.

The RBI plays a crucial role in ensuring the stability, efficiency, and soundness of the banking system. It formulates and implements monetary policies, issues banking licenses, sets prudential norms and regulations, conducts inspections and audits, and takes necessary measures to safeguard the interests of depositors and maintain financial stability.