[Solved] For a vertical demand curve, A) slope is undefined,and price elasticity of demand is equal to 0. B) slope is equal to 0,and price elasticity of demand is undefined. C) slope and price elasticity of demand both are undefined. D) slope and price elasticity of demand both are equal to 0. Energy Source: null Transferrin Receptors: null Receptor-Mediated Endocytosis: null HFE: null