20. Which of the following is an implication of rational expectations theory?
(A)Deviations of output from the natural rate are likely to be serious and long-lived.
(B) The economy is like a complex machine, that needs to be optimally controlled with the properpolicy.
(C) Macroeconometric models based on past behavior will not be very useful in formulatingpolicy.
(D)Wages and prices are set almost entirely at random, so it is pointless to try to model theirbehavior.
(E) Business cycles almost always result from a shift in aggregate demand.