New disposal fees for toxic chemicals used in producing plastic house plants have increased production costs by $ 0.28 per plant for all manufacturers in the industry. The most likely effects on the industry supply curve and total producers’ surplus in the market for plastic house plants are: Industry supply Producers’ surplus（） ①A. shifts left increases ②B. shifts left decreases ③C. shifts right decreases
A. ①
B. ②
C. ③
参考答案：B
解析：
An increase in production costs will decrease industry supply and the supply curve will shift to the left(less quantity supplied at each price). Assuming a downward sloping industry demand curve and no other change in the costs of production, the increase in per-unit cost will decrease producers’ surplus in the plastic plant industry.