(a) The improvements listed in these Regulations have been satisfactorily completed prior to such approval, or
(b) The subdivider files with Council a surety bond or cashier's or certified check for the amount of 120 percent of the estimated construction cost which shall be approved by the City Engineer, guaranteeing to the City that such improvements will be constructed and completed in a satisfactory manner and within a period specified by the City Engineer, and such guarantee shall extend one year beyond completion. Such bond or checks shall be approved by the Law Director and shall be made payable to and enforceable by the City of East Liverpool, Ohio. Upon satisfactory completion of the improvements and approval of the same in writing by the City Engineer and with the presentation of letters of certification of payment in full of all contractors, subcontractors, suppliers of materials, engineers, surveyors and all inspection fees or other fees incurred by the installation of the improvements by the subdivider, the bonds may be released in writing by Council and may be returned to the developer.