单选题 Which of the following most accurately describes a market structure that has one seller of a specific, well-defined product that has no good substitutes?

A、

A. Oligopoly.
B、

B. Monopoly.
C、

C. Monopolistic competition.

【正确答案】 B

【答案解析】A monopoly is characterized by one seller, a specific and well-defined product for which there is no good substitutes, and high barriers to entry.