(iii) If service is to be made on an owner of a dwelling who has not filed such a registration statement in relation to such dwelling, or on a managing agent of any such dwelling who has not been designated under the applicable provisions of article two of this subchapter, by posting a copy of such notice or order in a conspicuous place in such dwelling, or by delivering a copy thereof to any person of suitable age and discretion in charge of or apparently in charge of such dwelling, or by mailing a copy thereof to such owner or managing agent at the last known business or residence address of such owner or managing agent.
b. Any such notice directed to an owner of a dwelling or tenant of any space therein need not designate such owner or tenant by name, but shall refer to such dwelling or space by a description which shall be sufficient to identify same and shall state that it is directed to the owner of such dwelling or tenant of such space, as the case may be.
c. Where a designation of a managing agent under the applicable provisions of article two of this subchapter is currently in effect as to any multiple dwelling, any notice mentioned in subdivision a of this section which is directed to the owner of such multiple dwelling shall also be directed to such managing agent, and shall be served by the department on both such owner and managing agent.