Which of these is related to public goods?

Correct option is D

Public goods are associated with the concept of free ridership, which means people can benefit from the good without contributing to its cost because public goods are non-excludable and non-rivalrous.
 Excludability applies to private goods where consumers can be prevented from consuming them if they do not pay.
 The clear link between producer and consumer through payment is a characteristic of private goods.
 Rivalrous consumption means that one person's consumption of a good reduces the quantity available for others, which is not a feature of public goods.