如题

问题如下：

QuestionWhich characteristic(s) hint(s) at the presence of a monopoly in the market?

选项：

A.

A sole firm holding a concentration ratio of 100%

B.

A Herfindahl-Hirschman index standing at zero

C.

Both a 100% concentration ratio and a Herfindahl-Hirschman index of zero

解释：

Solution

1. Correct, as a concentration ratio that equals 100% indicates that a single firm dominates the entire market, suggesting a monopoly.
2. Incorrect, since a Herfindahl-Hirschman index (HHI) at zero would not signify a monopoly. In fact, if a single entity holds a monopoly, the HHI would be at its maximum, not zero.
3. Incorrect, because while a concentration ratio of 100% does indicate a monopoly, a Herfindahl-Hirschman index of zero contradicts this. An HHI of zero suggests diverse market competition, whereas a monopoly would result in a maximum HHI value.

The Firm and Market Structures

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