In the above table, based on the four-firm concentration ratio, which industry is the most concentrated?

Diminishing marginal returns occur because

a. All inputs are variable in the short-run b. All inputs are variable in the long-run c. Some inputs are fixed and some inputs are variable in the short-run d. None of the above

If a binding price floor is imposed on the video game market, then

a. the demand for video games will decrease. b. the supply of video games will increase. c. a surplus of video games will develop. d. All of the above are correct.