Mackenzie, an agent for Lindsey, signs an agreement with Kirk on Lindsey's behalf but neglects to tell her that the agreement requires the payment of a certain tax. The government prosecutes Lindsey for failing to pay the tax. She is……

a) liable, because notice to Mackenzie is notice to Lindsey

b) liable, because notice to Kirk is notice to Lindsey

c) not liable, because Mackenzie did not tell Lindsey about the tax

d) not liable, because Kirk didn't tell Lindsey about the tax