receive 1 point. You get 0 point if you leave it blank. 1. Natural experiments on the demand for medical care: a. Are consistent with the findings of the RAND HIS. b. Suggest that prescription drugs and physician visits are substitutes. c. Suggest that travel time is also an important determinant of demand d. All of the above. 2. When studying physicians as economic agents, it is important to consider a. Inputs into a productive process. b. Entrepreneurs. c. All of the above