问题
单项选择题
The free-rider problem, an obstacle to efficiency, is most likely associated with:（）
A. monopolies
B. public goods
C. subsidies and quotas
答案
参考答案：B
解析：
Explain how resources move to the most efficient allocation, the obstacles to achieve efficiency, and whether or not competitive markets use resources efficiently public goods can be consumed simultaneously by everyone and it is not in each person's interest to buy her or his share of a public good.