An insurer may invest in bonds, debentures, or other evidences of indebtedness of local public housing authorities existing under the laws of the United States or of any state if such obligations are:
(1) Secured by a pledge of annual contributions unconditionally payable under the annual contributions contract between the Department of Housing and Urban Development and the local agencies issuing the bonds;
(2) Unconditionally guaranteed by the state, municipality, or political subdivision creating the authority, if the tax supported obligations of such state, municipality, or political subdivision so guaranteeing would be eligible for investment under this chapter; or
(3) Secured by payments to be made sufficient to pay principal and interest on the bonds under an "assistance contract" between the local authority and the state, municipality, or other political subdivision creating the authority; provided, the tax supported obligations of the assisting state, municipality, or political subdivision would be eligible for investment under this chapter.