Question

if a firm functions in an oligopoly, it

alone supplies an entire market .

has no close substitutes in a market.

is one of many suppliers of a good with perfect substitutes.

is the only firm in a geographic region.

one of a few firms that produces a good with close substitutes.

Explanation:

To solve this, we analyze each option based on the definition of an oligopoly:

• "Alone supplies an entire market" and "is the only firm in a geographic region" describe a monopoly, not oligopoly.
• "Has no close substitutes" is also a monopoly characteristic.
• "Is one of many suppliers of a good with perfect substitutes" describes perfect competition.
• "One of a few firms that produces a good with close substitutes" matches the oligopoly definition (a market structure with a few large firms, products may be differentiated or have close substitutes).

Answer:

one of a few firms that produces a good with close substitutes.