Correct Answer: Reserve Bank of India (RBI)

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

The Reserve Bank of India (RBI) is the highest monetary authority in the country. It is the central bank of India and plays a crucial role in formulating and implementing monetary policy. The RBI is responsible for regulating and controlling the banking system, managing the country's currency and foreign exchange reserves, and ensuring the stability of the financial system.

As the highest monetary authority, the RBI has the authority to issue and regulate the currency in India, set interest rates, manage foreign exchange reserves, and supervise and regulate banks and financial institutions. It operates independently from the government in its decision-making process, although it works in coordination with the Ministry of Finance and other government agencies to achieve the country's economic objectives.