Which of the Following Statements Is (Are)correct

Multiple Choice

Which of the following statements is (are) correct?

A) There is no fundamental difference between the monetarist and the Keynesian theories regarding whether business cycles are demand-driven or supply-driven.
B) In both the monetarist and Keynesian models,changes in the expected price level play an important role in the position of aggregate supply.
C) In both the monetarist and Keynesian models,the assumption of constant velocity is critical.
D) Both a and b
E) Both a and c