Monica and Omar Talk About the Fact That a New

Monica and Omar talk about the fact that a new teacher is being hired for business law at their school. Omar mentions that he does not yet have a book, and Monica agrees to sell Omar a used business law book for $30 for the upcoming semester. When the new semester begins, the new business law teacher announces that a new custom business law text will be used that is only available in the campus bookstore. Omar wants a refund. Which of the following is Monica's best defense?

A) That Omar knew of the change of teacher and bore the risk of mistake.
B) That only a unilateral mistake was involved on Omar's behalf because Monica was aware of the change and, therefore, Omar is not entitled to a discharge.
C) That a mutual mistake was involved and that Omar is, therefore, not entitled to a refund.
D) That transactions involving goods are not subject to the defense of mistake.
E) That she did not commit fraud and, therefore, Omar is not entitled to rescission.