想请问monopoly情境下的公司数量

问题如下：

In which market structure, advertising is least likely to be used for differentiation promotion?

选项：

monopolistic competition.

perfect competition.

oligopoly.

解释：

B is correct

In a market of perfect competition, the products are identical, thus there is no reason for advertising.

考点：市场结构

解析：完全竞争市场，产品都是同质的，没有差异，厂商通过广告宣传只会徒劳增加成本，所以B入选。

寡头以及垄断竞争市场上厂商生产的产品有一定的差异，所以厂家可以通过广告提高市场占有率，增加利润。