Every bid shall be accompanied by a certified check or a bid bond of any surety company authorized to do business in the Commonwealth of Pennsylvania, the same payable to the Borough of Monaca, in the amount of 5% of the bid to insure execution of the contract and delivery of a bond to guarantee the performance of the contract. No bid will be considered unless so guaranteed. Every certified check or bid bond will be held until the successful bidder has executed a written agreement of sale for the performance of the bid within twenty (20) days after notice of award of contract. In the event that the successful bidder fails to execute a written contract and thereby a default shall occur, the Borough of Monaca reserves the right, within the thirty-five (35) day period ensuing after bid opening to award the bid to the next lowest responsible bidder or reject all remaining bids.