Which statement is TRUE regarding the effects of monetary policy when a real shock occurs?

(a) Monetary policy can always be used to simultaneously achieve a high real growth rate and lower the inflation rate.
(b) Monetary policy cannot simultaneously achieve a high real growth rate and lower the inflation rate.
(c) Monetary policy can be used only to change the real growth rate, but not the inflation rate.
(d) Monetary policy can be used only to change the inflation rate, but not the real growth rate.