Having extricated your company from the International Widget fiasco, you get a proposal from American Widgets Corporation for a set of platinum widgets. The proposal says it is good for 30 days. Two weeks later you fax a signed purchase order to American Widgets. The next day in the mail you get a letter from American Widgets rescinding the offer. The letter was postmarked two days before you faxed your purchase order. Do you have an enforceable contract? Why or why not?