a. The owner of a multiple dwelling shall provide adequate janitorial services.
b. In a multiple dwelling of nine or more dwelling units, the owner shall either:
(1) Perform the janitorial services himself or herself, if he or she is a resident owner; or
(2) Provide a janitor; or
(3) Provide for janitorial services to be performed on a twenty-four-hour-a-day basis in a manner approved by the department.
c. The owner of a multiple dwelling or his or her managing agent in control shall post and maintain in such dwelling a legible sign, conspicuously displayed, containing the janitor's name, address (including apartment number) and telephone number. A new identification sign shall be posted and maintained within five days following a change of janitor.