(a) The term "appropriate city official" as used in this article shall mean any city employee designated by the mayor as the person to exercise the authority and perform the duties delegated by this article to the "appropriate city official."
(b) Whenever the appropriate city official finds that a building, structure, part of a building or structure, party wall, or foundation situated in the city is unsafe to the extent that it is a public nuisance, the official shall give the person or persons, firm, association, or corporation last assessed for state taxes and all mortgagees of record written notice to remedy the unsafe or dangerous condition of the building or structure or to demolish the building or structure within the time set out in this article, or that the building or structure may be demolished by the city and the cost thereof assessed against the property. A copy of the notice shall be served by first-class mail or by personal service.
(c) Notice of the order, or a copy thereof, prior to the delivery or mailing of the order as required by this section shall also be posted at or within three feet of an entrance to the building or structure. If there is no entrance, the notice may be posted at any location upon the building or structure.