Which of the following is most likely to be a bona fide and valid offer? a) "I will sell you my water skis for $25. Delivery will be at the end of the summer." b) "I intend to tell my water skis for $25 at the end of the summer." c) "I am planning on selling my water skis at the end of the summer". d) "Would you be interested in buying my water skis for $25 when summer is over