Christina is an economist who believes that shifts in aggregate demand cause both a change in real output and the price level. She believes that an economic recession will not necessarily self-correct in the long run, and therefore she believes that active fiscal and monetary policy is justified to smooth out the business cycle. Christina is best described as a _____.
A.classical economist.B.Keynesian economist.C.supply-side economist.D.monetarist.E.rational expectations economist.