Which of the following goods is nonrival?

• A. A private swimming pool
• B. A reserved seat at a concert
• C. A sandwich from a deli
• D. A public park that is open to everyone

Answer: (D)

Verified step by step guidance

1. Understand the concept of rivalry in consumption: A good is rival if one person's consumption of it reduces the amount available for others to consume.
2. Analyze each option by asking whether one person's use diminishes the availability for others:
3. For a private swimming pool, if one person uses it, others cannot use it at the same time, so it is rival.
4. For a reserved seat at a concert, once taken by one person, it cannot be used by another, so it is rival.
5. For a sandwich from a deli, once eaten by one person, it cannot be consumed by another, so it is rival.
6. For a public park open to everyone, one person's use does not significantly reduce availability for others, so it is nonrival.