When Assessing the Market Demand and Supply of Physicians, Economists

When assessing the market demand and supply of physicians, economists look at all of the following except

A) trends in the number of non-M.D. physicians, chiropractors, and physician substitutes.
B) trends in the retirement rates of physicians.
C) population growth.
D) academic publication records of practicing physicians.
E) the number of students applying to medical schools.