Each bid shall be on a form to be prescribed by the chief administrative officer, under direction of the mayor, and shall be accompanied by such cash deposit, certified check or bond as may be prescribed for the purpose of insuring the bidder's entering upon performance of the work in case his bid is accepted. Bids shall be opened publicly at the time and place fixed in the advertisement. Bidders whose bids are rejected shall be promptly notified and their cash deposits, checks or bonds thereupon returned to them. The bidder whose bid is accepted shall be promptly notified of the acceptance. The urban county council may reject any and all bids.