Consider the following problems: overcrowded public highways, overfishing in the ocean, polluted air, and the near-extinction of the wild rhinoceros. What do these problems have in common? Select one: a. Private markets could easily solve them if governments left the markets alone. b. They would all go away if the government sponsored an intensive public-information campaign. c. They are all the result of a failure to establish clear property rights over something of value. d. They are all the result of a failure of corrective taxes.