Gilligan's Island Tours, Inc. (GITI), runs three-hour cruises. Its articles of incorporation list only one corporate purpose, which is "the operation of three-hour cruises to nearby islands." Realizing that a desert island to which it sails would make a great resort, the chairman of the board of GITI, Skipper, signed a land sale contract on the corporation's behalf to purchase the island from Mary Ann, its owner. Before closing the deal, Mary Ann changed her mind and GITI brought a lawsuit to compel Mary Ann to go through with the sale. Mary Ann's best defense against enforcement of the contract would be