Final answer:
Common resources differ from public goods in that they are rivalrous in consumption, meaning the use by one person reduces the availability for others, which is not the case with public goods.
Step-by-step explanation:
Common resources differ from public goods in that b) unlike public goods, common resources are rivalrous in consumption. A public good is both non-excludable and non-rivalrous, which means that one person's use of the good does not diminish another's ability to use it, and it is not possible to prevent someone from using it. On the other hand, a common resource is non-excludable but is rivalrous; the use by one individual does reduce the availability for others, an example of this would be a fishing spot that can be depleted if overused. This fundamental difference is essential in economics as it affects how these types of goods are managed and provided within a society.