单选题 In a competitive market, the gains to society are maximized under which of the conditions described below?
Marginal Benefit Marginal Cost Producer Surplus Consumer Surplus
①A. $1.25 $1.00 $25 $25
②B. $1.50 $1.50 $45 $30
③C. $2.50 $2.50 $35 $35
  • A. ①
  • B. ②
  • C. ③
【正确答案】 B
【答案解析】In a competitive market, the efficient equilibrium quantity produced is the quantity where marginal benefit equals marginal cost and the sum of consumer and producer surplus is maximized.