Water Works had a long-standing policy of offering employees $100 for suggestions actually used.  Due to inflation and a decline in the quantity and quality of suggestions received, Water Works decided to increase the award to $500.  Several suggestions were under consideration at that time.  Two days prior to the public announcement of the increase to $500, a suggestion by Farber was accepted and put into use.  Farber is seeking to collect $500. Farber is entitled to
(A)$500 because Water Works had decided to pay that amount. (B)$500 because the suggestion submitted will be used during the period that Water Works indicated it would pay $500. (C)$100 in accordance with the original offer. (D)Nothing if Water Works chooses not to pay since the offer was gratuitous.
C