HELP PLEASE!!!!! 100 POINTS

What is the ecological impact of eutrophication on aquatic ecosystem?

A) There is less dissolved oxygen in the water for fish and other animals because bacteria use oxygen when decomposing the algae.

B) The food chains become less complex because primary consumers do not have to work as hard to obtain food.

C) The food chains become more complex because a new producer is introduced.

D) There is more dissolved oxygen in the water for fish and other animals because the algae are photosynthetic.