At the hearing the board shall hear any objections coming before it to any of the following:
(a) The petition.
(b) The formation of the improvement district.
(c) The land to be included within the improvement district.
(d) The plans and specifications.
(e) The estimate of cost.
(f) The proposed assessment.
(g) The apportionment of the assessment.
(Added by Stats. 1943, Ch. 372.)