(a) The district shall keep a complete system of accounts.
(b) The district shall have an annual audit of the affairs of the district performed by an independent certified public accountant.
(c) A signed copy of the audit report shall be delivered to each trustee not later than the 120th day after the closing date of each fiscal year.
(d) A copy of the audit report shall be kept on file at the district office and shall be made available for inspection by any interested person during regular business hours.