Changes in monetary policy occur when the Federal Reserve

adjusts business laws to affect the money supply.

changes taxation levels to affect the economy.

changes spending levels to affect the economy.

adjusts interest rates to affect the money supply.

The changes in the monetary policy can be controlled by the Federal Reserve. The Federal Reserve serves as the central bank of the United States and this controls all the financial activities of the economy. In this case, when there are changes in the monetary policy, what is done by the Federal Reserve is changing the spending levels to affect the economy. The answer would be the third option.