The Case for Federal Reserve Independence Includes the Idea That

The case for Federal Reserve independence includes the idea that

A) a politically insulated Fed would be more concerned with long-run objectives and thus be a defender of a sound dollar and a stable price level.
B) a Federal Reserve under the control of Congress or the president might make the so-called political business cycle more pronounced.
C) the principal-agent problem is perhaps worse for the Fed than for congressmen since the former does not answer to the voters on election day.
D) only A and B of the above.