A. The Council, in adopting a method of assessment of the costs of the improvement, may:
1. Use any just and reasonable method of determining the extent of any improvement district consistent with the benefits derived;
2. Use any method of apportioning the sum to be assessed that is just and reasonable between the properties to be specially benefited; and
3. Authorize payment by the city of all or any part of the cost of the improvement, when in the opinion of the Council, on account of topographical or physical conditions, unusual or excessive public travel or other character of the work is involved or when the Council otherwise believes the situation warrants it; provided, the method selected creates a reasonable relation between the benefits derived by the properties specially assessed and the benefits derived by the city as a whole.
B. Nothing contained in this section shall preclude the Council from using other available means of financing improvements, including federal or state grants-in-aid, sewer service or other types of service charges, revenue bonds, general obligation bonds or other legal means of finance. In the event any of these other means of finance are used, the Council may, in its discretion, levy special assessments under this section according to benefits to cover any part of the costs of the improvement not covered by those means.