问题如下：
If a market structure is characterized by similar or standardized products, and there are just a small number of sellers, it is most likely to be:
选项：
A. oligopoly.
B. perfect competition.
C. monopolistic competition.
解释：
A is correct
Oligopoly is a form of market competition characterized by a small number of sellers and similar or standardized products.
考点：市场结构
解析：题中提到厂商生产的产品是标准化的或者是相似的，并且生产厂商的个数很少，这些都符合寡头市场的特征。
寡头和垄断竞争的区别是什么 不太懂
