Economic policy that appears to be ideal in an economics textbook may not be the final policy that is approved by elected politicians because

a. sometimes a politician's self interest may conflict with the national interest.
b. economics professors have a notoriously low voting rate.
c. only policies advocated by the President's Council of Economic Advisors receive enough national attention to interest politicians.
d. Economists cannot explain why politicians do not implement the ideas from their textbooks.

a