The action that would be considered loosening monetary policy is:
The Federal Reserve lowering the reserve requirement.
Loosening monetary policy generally involves taking actions that increase the money supply and decrease interest rates, making borrowing cheaper to stimulate economic activity. Lowering the reserve requirement allows banks to lend more of their deposits, thereby increasing the money supply.
Increasing interest rates would tighten monetary policy, while both increasing government spending and lowering taxes are fiscal policy actions rather than monetary policy actions.