问题
单项选择题
If the market demand for a product decreases in a competitive market, then the quantity supplied by an individual firm will:（）
A. decrease and firms will exit the market in the long run.
B. decrease and firms will enter the market in the long run.
C. increase and firms will enter the market in the long run.
答案
参考答案：A
解析：
If the market demand for a product decreases in a competitive market, then the quantity supplied by an individual firm will decrease and firms will exit the market in the long run because the price will be less than average total costs.