At its option, the board of directors of a district may adopt a resolution declaring its intention to dispense with either the office of assessor or both the offices of assessor and collector of the district, and to transfer the duties of either the assessor or of both such officers to the assessor or to the assessor and tax collector of the county or counties in which the lands within such districts are located. Such resolution shall specify whether, under the proposed procedure, lands subject to sale for unpaid assessments shall be sold to the district or be declared tax-defaulted for nonpayment of the taxes.