The time of opening of such tenders shall be not less than five days after the last publication. All bids shall be sealed and delivered to the officer advertising therefor and shall be opened by the officer at the hour and place to be stated in the call for tenders in the presence of all bidders who attend, and may be inspected by any bidder. All bids which do not comply with the requirements of the call for tenders shall be rejected. The officer calling for bids may reject any or all bids and waive any defects when in the officer’s opinion such rejection or waiver will be for the best interest of the public.