(1) A credit union may invest, without dollar limitation, in the general obligations of:

(a) any state of the United States if the obligations are fully guaranteed as to the repayment of principal and interest. Evidence of a full guarantee includes, but is not limited to, the pledge of the full faith and credit of the state responsible for repayment of the general obligation; and

(b) any Montana political subdivision if:

(i) the obligations are issued pursuant to the Constitution, statute, or the charter or ordinances of the respective county or city;

(ii) the obligations are fully guaranteed as to the repayment of principal and interest. Evidence of a full guarantee includes, but is not limited to, the pledge of the full faith and credit of the Montana political subdivision responsible for repayment of the general obligation; and

(iii) the issuing body has not been in default regarding the payment of principal or interest on any of its obligations within five years preceding the date of the investment.