问题
单项选择题
In perfectly competitive constant-cost industries and perfectly competitive increasing-cost industries, respectively, what is the most likely long-run effect of a permanent increase in demand ncreasing-cost industry Constant-cost industry（）①A. price decreasesprice decreases ②B. price decreasesprice remains unchanged ③C. price remains unchangedprice decreases
A. ①
B. ②
C. ③
答案
参考答案：B
解析：
In the case of constant-cost industries, the long-run supply curve is perfectly elastic or horizontal. Therefore, a permanent increase in demand would have no effect on the price in the long run. In the case of an increasing-cost industry, the long-run supply curve slopes upward and a permanent increase in demand would result in :an increase in the price.