All notices and other communications required or permitted to be given under this Agreement shall be in writing and shall be deemed to have been duly given (a) when delivered personally; (b) if sent by facsimile, when receipt thereof is acknowledged at the telecopy number below; (c) the day following the day on which the same has been delivered prepaid for overnight delivery to a national air courier service; or (d) five (5) business days following deposit in the United States Mail, certified, postage prepaid.