Sec. 4. The fund or any part of the fund may be invested in securities bearing the rate of interest that is obtainable as follows:
(1) In bonds, notes, or certificates that are the obligations of, or guaranteed by, the United States.
(2) In:
(A) bonds of any territory or insular possession of the United States;
(B) bonds, notes, warrants, certificates, or orders of the state of Indiana; or
(C) any political subdivision, instrumentality, or agency of the state of Indiana;
issued under authority of law.