中等econ-u03-d04
A pure public good is characterised by being:
A. Non-rival and non-excludable✓ 答案
B. Rival and excludable, like a pizza
C. Sold only by private firms to the highest bidder
D. Free to consume but rival in use
解說
Non-rival means one person's use does not reduce another's; non-excludable means people cannot easily be prevented from using it. Together they create a free-rider problem, which is why public goods are often funded by the government.