Answer:
b. bike path around a city or town
Explanation:
A public good is a good which is both non excludable and non rival. This means that the good is open for everyone to use and no one can restrict its acces for others. Furthermore, the consumption of good by one individual doesnot reduce its quantity or consumption for the others. A bike path around a city or town can be used by anyone and no one can restrict its use and its consumption by one will not reduce its consumption for other so it is a public good.
