The U. S. government protects fish, a common resource, byA. subsidizing the fishing industry. B. heavily taxing competing industries. C. selling fishing licenses and regulating fish lengths. D. None of the above is correct.

Option C, selling fishing licenses and regulating fish lengths

Explanation:

The United States Fish and Wildlife Service agency is mainly responsible for protecting fishes. It issues license to fish in order to prevent massive hunting. Licensing allows the license holder to fish uninterruptedly while the people who do not have license cannot fish. However, some regulations are to be followed by license holder for regulating fishing. There is limit on the species and their sizes

Hence, option C is correct