Questions: QUESTION 23 When not congested, roads and will are O non-rival, non-excludable O excludable, non-excludable O non-rival, excludable O rival, non-rival But when too many people are using them, congestion makes them

The answer is non-rival, excludable

This option describes public goods, which are available to everyone without reducing availability to others and cannot exclude anyone from using them. Roads, when not congested, do not fit this description because they can be excludable through tolls or access restrictions.

This option is contradictory as it suggests that roads can be both excludable and non-excludable at the same time, which is not possible.

This is the correct option. When roads are not congested, one person's use does not diminish the ability of others to use them (non-rival). However, they can be excludable through mechanisms like tolls or restricted access.

This option is also contradictory as it suggests that roads can be both rival and non-rival at the same time, which is not possible.

When too many people are using them, congestion makes roads rival because one person's use can diminish the ability of others to use them effectively.