What are three positive effects of diverting or stopping the flow of river water

Diverting the flow of river water can cause both negative and positive effects. Although there are more negative than positive effects, we are going to focus on the positive effects. The flow diversion by building a dam can benefit humans. This will have a big impact on the agricultural aspect of the society. This can also be used to generate power. 

Iagree c would be the answer