Open-market operations include: a) repos and reverse repos. b) changes in the discount rate. c) changes in the reserve ratio. d) paying interest on excess reserves held at federal reserve banks.

Open market operations include repo and reverse repo.

Explanation:

Open market operation is a policy in which there is increase and decrease of cash with the people. , this is done through sale and purchase of securities by the central bank. When there is more cash in the market then the actual quantity then , the central bank try to sell the securities . Selling of securities to the people help the central bank in soaking  the purchasing power from the market . On the other hand , when there is less cash then the actual one in the market then the central bank try to purchase the securities. Purchasing of securities help in increasing the purchasing power of the people.

The Open market operation is the monetary policy of the government .