Final answer:
The first goals of the Clean Water Act focused on identifying and controlling point-source pollutants which include discharges from factories and sewage treatment plants, as well as runoff from animal factory farms and combined sewer systems. The correct option is a) point-source pollutants.
Step-by-step explanation:
The first goals of the Clean Water Act were to identify and control point-source pollutants. These pollutants enter water supplies from identifiable and relatively small locations, such as pipes from factories or sewage treatment plants.
Additionally, animal factory farms raising a large number of livestock, and combined sewer systems can be significant point sources of pollution, especially when rainfall causes them to exceed capacity, resulting in untreated sewage spilling into surface waters.