Answer:D-It is extremely difficult to limit the benefits of a public good to the people who pay for it.
Explanation:
The above statement is true as public goods and services are available to all and not only for payers. For Example the tax paid by a group of will not only benefit the tax payers but also provides goods and services to the non tax payers like Police services, roads ,Hospitals, Infrastructure etc.
Thus option D is most appropriate.