Final answer:
None of the options provided, a tuna in the ocean or a visit to the doctor's office, are nonrival goods. A nonrival good is one that can be consumed by many people at the same time without affecting each other's consumption, such as public radio.
Step-by-step explanation:
The student's question involves determining which goods are nonrival in consumption. A good is considered nonrival if one person's use of the good does not diminish another person's ability to use it. Of the two options provided:
- A tuna in the ocean is rival because one person catching it prevents another from doing so.
- A visit to the doctor's office is also rival because the doctor can only see one patient at a time, making it impossible for multiple people to consume this service simultaneously.
Hence, none of the provided options are nonrival. From the examples given for reference, public radio is a nonrival good because it can be listened to by many people at the same time without one person's use detracting from another's.