Consider the Following Scenario: a Fish That Was Normally Found

Consider the following scenario: A fish that was normally found in freshwater has evolved and can now survive in brackish water which contains a mixture of fresh and salt water. How would this affect other levels of biology?

A) The evolution of the fish would affect all other levels of biology, including other populations, communities, and ecosystems.
B) The evolution of the fish would only affect the population of that fish species.
C) The evolution of the fish would only affect the community in which it occupies.
D) The evolution of the fish would only affect the organisms it eats.