(b) Last known address.--For purposes of this local law, a taxpayer's last known address shall be the address given in the last return filed by him, unless subsequently to the filing of such return the taxpayer shall have notified the administrator of a change of address.
(c) Last day a Saturday, Sunday or legal holiday.--When the last day prescribed under authority of this local law (including any extension of time) for performing any act falls on Saturday, Sunday, or a legal holiday in the state of New York, the performance of such act shall be considered timely if it is performed on the next succeeding day which is not a Saturday, Sunday or a legal holiday.