Which characteristic is a firm least likely to exhibit when it operates in a market with a downward sloping demand curve, many competitors, and zero economic profits in the long run?
A. diffrentiated product
B.low barriers to entry
C.no pricing power
答案选C，并且解析说这是monopolistic competition，因为有向下的需求曲线。我的问题是，“with a downward sloping demand curve”如果形容的是market，那么也可以是完全竞争市场，不是说完全竞争市场的firm的需求曲线是水平的，而market的需求曲线是向下的吗？从题目的描述来看，怎么可以确定不是完全竞争市场呢？谢谢。