问题如下：
In a perfectly competitive market, the firm's short-term shutdown point is:
选项：
A.where the average total cost curve intersects with its price level.
B.where the marginal revenue curve intersects with marginal cost curve.
C.where the marginal revenue curve is below the average variable curve.
解释：
C is correct.
When marginal revenue curve is below average variable cost curve, the firm will face a loss. Therefore, it is at the short-term shutdown points.
考点：停止营业点
解析：当边际收益小于平均可变成本时，厂商就应该停止营业。所以应该选C
老师，好：
首先，这道题c项少个cost。其次，这道题目题干是shutdown point is，所以c项应该是equal的时候，which is AVC=MR的时候。如果是below的话，题干应该的问法是公司何时停业。我觉得这样比较严谨点。
