In the Friedman-Lucas money surprise model, suppose that the central bank wants to reduce the price level.

Question:

In the Friedman-Lucas money surprise model, suppose that the central bank wants to reduce the price level. Suppose the central bank has two options: (i) announce in advance that the money supply will decrease; (ii) surprise the public with a decrease in the money supply.
Which option is preferable? Explain with the aid of diagrams.