To determine whether the benefits of the Grand Forks flood mitigation outweighed the costs, you'd typically analyze the data presented in the chart (which isn't provided in this case). Generally, this analysis involves comparing numerical values of benefits (like reduced damages, saved properties, and economic advantages) against the costs incurred in implementing flood mitigation measures (such as construction expenses, maintenance, and operational costs).
If the benefits significantly exceeded the costs, it would indicate that the flood mitigation efforts were financially justifiable, supporting the first response: "The benefits of flood mitigation were greater than the costs." Conversely, if the costs were greater than the benefits, the second response would apply: "The costs of flood mitigation efforts were more than the benefits."
Without specific figures or comparison data, it’s essential to rely on the information that you have to make a judgment. If it were demonstrated that the benefits did indeed outweigh costs, then select the first response. If not, choose the second. If there's insufficient data for comparison, the final option would be applicable.