Solving a tragedy of the commons problem could be done through:

I. societal expectations.

II. tradeable allowances.

III. government command and control methods.

 

a. II and III only

b. I, II, and III

c. II only

d. I and II only

Option b, I, II and III is the correct choice.

When the problem like tragedy of commons arises, this problem is solved when people or society collectively decided to take action and reduce their overutilization of scarce resources. So statement I is correct. If people does not do anything by their own then the government assigns property rights to certain group of individuals and allow them to trade those rights, which shows the validation of statement II. If this does not work, then the government uses command and control methods like imposing taxes and commanding people to adhere to the rules and hence controlling them which reflects the validation of statement III as well.