Bulk Baked Foods Company Agrees to Supply Comida Café with All

Bulk Baked Foods Company agrees to supply Comida Café with all the corn chips that it requires for a year. A sudden blight caused by an organism hitherto unknown in the United States results in a shortage of corn, and the price rises sharply. Bulk asks Comida to pay a higher price for the chips. This request is most likely

A) invalid as an attempt at extortion or the so-called holdup game.
B) invalid under the preexisting duty rule.
C) valid as a risk ordinarily assumed in business.
D) valid due to the unforeseen difficulty of the sharp price increase.