If a Central Bank Had to Give Up Its Discretion

Multiple Choice

If a central bank had to give up its discretion and had to follow a rule that required it to keep inflation low, how would the Phillips curve shift?

A) The short-run Phillips curve would shift up.
B) The short-run Phillips curve would shift down.
C) The long-run Phillips curve would shift right.
D) The long-run Phillips curve would shift left.