(a) The interest and sinking fund of a district must be permanently maintained in the bank where bonds of the district are payable.
(b) A district to which money is paid under Section 1501.207 shall promptly deposit that money, as well as other applicable money and investments of the district, to the credit of the interest and sinking fund of the district.
(c) A bank of payment that receives a deposit of money or an investment shall hold that money or investment in trust for the benefit of the holders of outstanding bonds of the district.