Define non-rivalry and provide a classic example.

• A. Non-rivalry means one person's consumption reduces another's; e.g., a sandwich.
• B. Non-rivalry means goods are excludable and rival, e.g., a movie ticket.
• C. Non-rivalry means one person's consumption does not reduce another's; e.g., broadcast news.
• D. Non-rivalry means goods are non-excludable but rival.

Answer: (C)

Non-rivalry means that one person's use of a good does not diminish another person's ability to use it. This is a defining feature of public goods. A classic example is broadcast news: watching the news is non-rival because my viewing does not reduce the availability or quality of the news for someone else, and many people can consume it at the same time without decreasing each other's enjoyment. In contrast, a sandwich is rival because once one person eats it, others cannot. The other descriptions mix in ideas like excludability or rivalry that don’t fit non-rivalry, whereas non-rivalry centers on simultaneous consumption without diminishing others’ use, with broadcast news as the standard illustration.