Choice "A" is correct. In order to form a contract, there must be at least an offer, an acceptance, and consideration. Card's communication is an offer. The stereo and the $250 would be the consideration for the contract here. But, Card will not be bound until Bend accepts the offer.
Choice "c" is incorrect. As a general rule, silence cannot constitute an acceptance, and Bend cannot be liable on a contract until it is accepted. If Bend remains silent, no contract is formed and Bend has no liability.
Choice "d" is incorrect. Card owes no contractual duties to Bend until Bend has accepted Card's offer. Thus, there is no duty to mitigate here.
Choice "b" is incorrect. An offeree may reject an offer at any time.
