Assume there is no way to prevent someone from using an interstate highway, regardless of whether or not he or she helps pay for it. This characteristic is called

A) nonrivalry.
B) nonexcludability.
C) nontaxability.
D) nondiscrimination.

Nonexcludability refers to the characteristic of a good or service that makes it difficult, if not impossible, to prevent non-paying users from accessing or benefiting from it. In the case of an interstate highway, it is difficult to prevent people from using it even if they do not pay for it, making it nonexcludable. Nonrivalry refers to the characteristic of a good or service that can be used or consumed by multiple users without diminishing its availability or quality. Nontaxability and nondiscrimination are not relevant characteristics in this context.