(a) If the board shall finally order the making of the proposed improvement, notice shall be given asking for bids for such work, which notice shall describe in a general way the character and approximate quantities of such work and the types of materials, including alternates, if any, to be employed and shall be published once a week for two consecutive weeks in a newspaper published in each county in which any part of the improvements will be constructed and having general circulation therein. The date for receiving bids as set out in the said notice shall be not earlier than two weeks after the date of first publication thereof.
(b) The board must let the contract to the lowest responsible bidder; provided, that if the lowest responsible bidder has not bid a satisfactory price, the board may reject all bids and readvertise for bids in the same manner as provided in this section.
(c) The board may, by order, impose further conditions upon bidders with regard to bonds and surety for the faithful completion of such work according to contract or for any other purpose mentioned in the specifications. Surety bond for the faithful completion of the said work shall be required where same or any part thereof is let out by contract in an amount not less than 50 percent of the estimated total of each contract.
(d) The authority may elect to construct the improvement or furnish labor or material or both for the same without asking for bids for that part of the improvement. In the event that the authority makes any such election, then the provisions of this section requiring the authority to ask for bids from contractors and to publish a notice with respect thereto shall not be applicable to any work of construction to be performed by the authority or to any labor and material, or either to be furnished by the authority.