All bonds issued by joint highway districts shall be legal investments for the funds of:
(a) Trusts.
(b) Insurance companies.
(c) Banks, both commercial and savings.
(d) Trust companies.
(e) State schools.
(f) Any other body whose funds may be invested in bonds of cities, counties, school districts or irrigation districts within the State of California.
(Added by Stats. 1943, Ch. 284.)