If the board determines that only a portion or certain portions of the tract of land described in the petition for inclusion of lands should be included, the petition shall be dismissed unless:
(a)
The petitioners include a majority of the holders of title or evidence of title of such portion, or of each of such portions, of the tract, representing also at least one-half the area of such portion, or of each of such portions; or
(b)
Within 60 days from the time such determination is made, there is filed with the board the consent in writing, acknowledged or proved as required in Section 75861, of a majority of the holders of title or evidence of title of such portion, or of each of such portions, of the tract of land, representing also at least one-half of the area of such portion or each of such portions.