[Overstock] Mark Owns an Electronic Resale Store

[Overstock] Mark owns an electronic resale store. Before Mark left for the weekend, he told Charlie, an employee, not to purchase any more compact discs (CDs) from customers because they were already having a difficult time selling the ones they had in stock. While Mark is gone, Charlie forgets Mark's instructions and buys nine CDs from customers.
-Which of the following statements is true regarding Charlie's liability to Mark?

A) Charlie is not liable to Mark because he did not remember Mark's instructions.
B) Mark may recover the cost of the nine CDs because Charlie did not follow his instructions.
C) Charlie is not liable to Mark because he thought the purchase price of the CDs were exceptionally great.
D) Charlie is not liable to Mark because he is his employee.
E) Charlie is not liable to Mark because he believed Mark would have bought the CDs from the customer.