(a) An obligation issued under this subchapter must mature not later than 40 years after its date of issuance.
(b) The obligations must be signed by the presiding officer or assistant presiding officer of the public utility agency and be attested by the secretary.
(c) A public utility agency may sell obligations issued under this subchapter at public or private sale at a price or under the terms the agency determines to be in the best interest of the agency.