There Is Considerable Discussion of Whether an Activist Policy Approach

There is considerable discussion of whether an activist policy approach is preferable over a strict rule approach.In this discussion, which of the following has been established?

A) active policy is not impossible, but a full-employment bias may create too much inflation
B) no activist policy rule has ever been created
C) no exceptions to the imposed rule should ever be made even under extreme circumstances, otherwise policy makers lose credibility
D) the economy can successfully be fine tuned as long as monetary policy decisions are announced in advance
E) none of the above