In any case where an administrative citation is issued, service of the citation shall be made by complying with the following:
A. Personal Service. The Animal Control Officer, or other authorized officer, shall attempt to locate and personally serve the responsible person and obtain the signature of the responsible person on the administrative citation. If the responsible person refuses or fails to sign the administrative citation, the failure or refusal to sign shall not affect the validity of the administrative citation or of subsequent proceedings; or, if the responsible person cannot be contacted and personally served after reasonable efforts to do so have failed, service may be effected by certified mail.
B. Mail and Posting. The responsible person, shall be served by certified mail, return receipt requested. Simultaneously, the citation shall be sent by first class mail. If the citation is sent by certified mail and returned unsigned, then service shall be deemed effective pursuant to first class mail, provided the citation sent by first class mail is not returned.