A、-2
B、0
C、2
D、-7

单项选择题汽车电路图中用来表示熔断器的图形符号是（）A. B. C. D.

单项选择题The Canadian metal chair manufacturing market has n = 78 firms. The estimated elasticity of supply is ηo = 3.1, and the estimated elasticity of demand is ε = - 1.1. Assuming that the firms are identical, calculate the elasticity of demand facing a single firm.