(a) The comptroller shall appoint a chief clerk who shall:
(1) perform the duties of the comptroller when the comptroller is unavoidably absent or is incapable of discharging those duties;
(2) act as comptroller if the office of comptroller becomes vacant until a comptroller is appointed and qualified; and
(3) under the comptroller's direction, supervise the keeping of the books, records, and accounts of the office and perform other duties required by law or the comptroller.
(b) The chief clerk shall take the official oath.