Correct Answer: National Bank for Agriculture and Rural Development (NABARD)

Solution : The correct answer is (b). National Bank for Agriculture and Rural Development (NABARD)

NABARD is an apex development bank in India that focuses on agricultural and rural development. It plays a key role in promoting and overseeing the operations of regional rural banks (RRBs) to ensure their effective functioning and compliance with regulatory guidelines.

The Reserve Bank of India (RBI) is responsible for regulating and supervising commercial banks and other financial institutions in India. The Securities and Exchange Board of India (SEBI) is the regulatory body for the securities market in India and is not directly responsible for regulating regional rural banks.