The board may transfer to the general fund of the county any money obtained from the levy of an assessment for an improvement district if:
A. bonds or assignable certificates were issued to finance the improvement;
B. the proceeds of the bonds or assignable certificates were spent for the improvement;
C. the assessments were levied and collected for the payment of the bonds or assignable certificates; and
D. either the bondholders or assignable certificate holders are barred by the statute of limitations or a court judgment or decree from collecting the indebtedness; or
E. the bonded indebtedness or assignable certificates have been paid.