(2) A resolution shall be posted in three public places in the subdivision for five days. Within 10 days from the date when the resolution is posted, the owner of any property within a tract may file with the secretary a written remonstrance against the proposed improvement or employment. The board hearing the remonstrances may, in its discretion, overrule any remonstrance and, by resolution, order construction, repair or maintenance of the improvements. The board may either enter into a contract to complete the improvement or, in its discretion, complete the improvement under its own supervision. After the work on the improvement is completed the board shall, by resolution, apportion the costs and declare an assessment upon each tract benefited. The assessments declared under this section shall be final and conclusive. [Formerly 545.412]