In a Popular Resort Town, Many Dead Fish Were Found

In a popular resort town, many dead fish were found floating on the surface of the main swimming lake. What was the likely cause of the fish death?

A) The lake was eutrophic, and the low phytoplankton production caused a collapse in the lake's food chain.
B) The lake was eutrophic, so algal blooms caused low oxygen in the profundal zone.
C) The lake was oligotrophic, and, thus, higher trophic levels could not be supported by the reduction in phytoplankton/zooplankton production.
D) The lake was oligotrophic, so algal blooms caused low oxygen in the limnetic zone.
E) Artificial eutrophication caused an overproduction of phytoplankton, leading to a CO₂ buildup in the limnetic zone.