Donatello and Raphael are sitting around eating pizza and talking about cars. Donatello asks Raphael if Raphael would consider selling his car for $2,000. Is this a valid offer? Yes, an offer has been made by Donatello, but it may be revoked prior to acceptance. No, there is no valid offer here. This is just an invitation to negotiate. Yes, this is a unilateral offer, which Donatello can accept by performance. Yes, an offer has been made because Donatello and Raphael negotiated