Public Goods: Non-Excludable and Non-Rival

Steps:

• Define excludable: Can prevent non-payers from using the good.
• Define rival: One person's use reduces availability for others.
• Identify public good traits: Free access for all, no depletion from shared use.
• Match to option C: Non-excludable (free access) and non-rival (unlimited sharing).

Why C is correct:

• Economics defines public goods as non-excludable (impossible or costly to exclude users) and non-rival in consumption (one user's benefit doesn't diminish others'), like national defense.

Why the others are wrong:

• A: Describes club goods (excludable but non-rival, e.g., cable TV).
• B: Describes common resources (non-excludable but rival, e.g., public fisheries).
• D: Identical to B, describes common resources.

Final answer: C