Whenever under this Lease a provision is made for notice of any kind, it shall be deemed sufficient notice and service thereof if such notice to Tenant is in writing addressed to Tenant at his last known post office address, or at the demised premises, and deposited in the mail, certified or registered mail, with postage prepaid, and if such notice to Landlord is in writing addressed to the last known post office address of Landlord and deposited in the mail, certified or registered mail, with postage prepaid. Notice need be sent to only one Tenant or Landlord where Tenant or Landlord is more than one person.