The correct answer is option 1: Operation of current account and savings bank accounts. The Reserve Bank of India (RBI) is the central bank of India and has several functions. Let`s analyze each option to understand why option 1 is not a function of the RBI.

Option 1 states that the RBI operates current account and savings bank accounts. However, it is important to note that the RBI does not directly operate bank accounts for individuals or businesses. Instead, it regulates and supervises banks that provide current and savings bank accounts to the public.

Option 2 states that the RBI regulates and controls foreign exchange. This is a correct function of the RBI, as it is responsible for maintaining the stability of the foreign exchange market and managing the country`s foreign exchange reserves.

Option 3 states that the RBI oversees the commissions and omissions of the various units of the banking sector. This is also a correct function of the RBI, as it supervises and regulates banks to ensure compliance with banking laws and regulations.

Option 4 states that the RBI initiates steps to stabilize and control money supply and the rate of inflation. This is another correct function of the RBI, as it formulates and implements monetary policies to maintain price stability and control inflation.

In conclusion, option 1