The correct answer is Trading in securities by RBI. An open market operation is an activity undertaken by the central bank to give or take liquidity in the country's currency. It is given or taken from the bank or group of banks. In this method, the Central bank buys or sells government bonds in the open market. To reduce credit in the market Reserve Bank of India sells government securities thus reducing the supply of money in the market so there will be less money in the hands of commercial banks and the common public.