The correct answer is option D
If a new waste water treatment plant is opened in an area it will be full of bacterial toxin and nutrient.
Sewage usually contains bacteria and nutrients and is directly discharged into the bay.
The bacterial toxin and nutrients can cause different kinds of infection and form algal bloom in water respectively.
Excessive nutrients in water will lead to the growth of algae in the water and will decrease the oxygen content of water in later days.
