When it comes to macro-policy, most economists now agree that

a. policy should be constantly changing in response to business cycle conditions.
b. policy changes should exert stimulus during inflationary booms and restraint during downturns.
c. given our ability to forecast economic conditions, policy changes easily can be implemented in a timely manner.
d. policy changes are difficult to time correctly, and therefore constant shifts in policy are likely to be a source of economic instability.

D