Research conducted by edward prescott of arizona state university, and edward glaeser of harvard university along with bruce sacerdote of dartmouth college indicate that the effects of supply-side policies a. are, as of now, unclear and require more careful study. b. have little or no effect at all. c. are clearly defined and small. d. are clearly defined and substantial.

The correct answer is A) are, as of now, unclear and require more careful study.

Research conducted by Edward Prescott of Arizona State University and Edward Glaeser of Harvard University along with Bruce Sacerdote of Dartmouth College indicates that the effects of supply-side policies are, as of now, unclear and require more careful study.

When we are talking about economics, supply-side policies are thought to increase Aggregate Supply. They improve the productive capacities of an economy at the same time these are enhancing the quality of the factors of production that are land, labor, capital, and entrepreneurship.  But as academic Professors, Prescott  Glaeser, and  Sacerdote have concluded, supply-side policies are not easy to implement and its effect take time.

could you go a bit more in depth with you question? it's quite hard to understand. as soon as you do that i will be glad to : )