What defines private goods?

Private goods are characterized by two main properties: excludability and rivalrous consumption. Excludability means that sellers can prevent others from using the good, which enables them to charge for it. Rivalrous consumption indicates that one person's consumption of the good diminishes the ability of another person to consume it.

For instance, when you purchase a sandwich, you have the right to consume it exclusively, preventing others from eating it. This exemplifies both the excludable and rivalrous nature of private goods. If you eat the sandwich, it is no longer available for someone else, highlighting how the consumption by one person impacts another's opportunity to consume that same good.

In contrast, goods that are nonexcludable allow for use by everyone, regardless of whether they have paid for them, and nonrival goods can be consumed by multiple people without reducing availability for others, which is not applicable to private goods. Hence, the definition is clearly aligned with the characteristics of excludable and rival goods, validating the correct answer.