In Addition to Filling Lakes with Sediment,why Is Eutrophication a Biological

In addition to filling lakes with sediment,why is eutrophication a biological concern?

A) Filling lakes is the only major concern.
B) Excess algal growth leads to high levels of dissolved oxygen.
C) Excess algal growth makes it difficult for primary consumers to find food.
D) High levels of nutrients are toxic to algae.
E) When the algae die and decompose,dissolved oxygen levels drop.