Consider the Supply Curve Q^s = 2P and the Demand

Multiple Choice

Consider the supply curve Q^s = 2P and the demand curve Q^d = 90 - P. Which expression best shows how you would calculate the elasticity of demand when P increases by 1 along the demand curve from its equilibrium value?

A) [(59 - 60) / (31 - 30) ] x (30/60)
B) [(56 - 60) / (31 - 30) ] x (30/60)
C) [(59 - 61) / (31 - 30) ] x (30/60)
D) [(59 - 62) / (32 - 30) ] x (30/60)