Any notice to the Company under the Stock Option Documentation must be in writing and addressed to the Company in care of its Secretary at 1010 Grand Boulevard, Kansas City, Missouri 64106. Any notice to You under the Stock Option Documentation must be in writing and addressed to You at the address last known and on file with the Company. Notices must be delivered as follows (with notice deemed given as indicated): (i) by personal delivery, upon delivery; (ii) by nationally recognized express courier, upon delivery; (iii) by certified or registered mail, postage prepaid and return receipt requested, upon delivery; and (iv) by first-class U.S. mail, postage prepaid, three (3) calendar days following delivery to the United States Postal Service.