Which of the following is not an aspect of Keynesian economics? a. Wages and prices tend to be inflexible downward. b. Supply does not necessarily generate its own demand. c. The interest rate is important in determining the level of investment, but not as important as other variables such as income, taxes, expectation of future profits and losses and optimism and pessimistic sales of businesses. d. The U. S. economy is self regulating, so there is no interference from the government and the market will be in equilibrium in the long run. a. All of the above.