Each of the Following Is Something That Economists Know About

Each of the following is something that economists know about business cycles, unemployment, and inflation in the short run except

A) that aggregate demand interacts with aggregate supply - the Phillips curve - to generate the inflation rate.
B) that the expected rate of inflation hardly ever changes.
C) that the natural rate of unemployment can undergo substantial shifts in a much more rapid time scale . than the changing composition of the labor force would suggest possible.
D) that aggregate demand is the principal determinant of the level of real GDP in the short run.