Which of the statements is true about monetary policy?

a) Decrease in the money supply lowers short-term interest rates and encourage investment and consumption demand.

b) Monetary policy is determined by the Congress.

c) Higher money supply does not have a permanent effect on economic activity because it results only in a higher price level in the long run.

d) Monetary policy has the most immediate impact on the economy, but implementation of such a policy is usually slow.