Given the task definition and input, reply with output. In this task, you are given a multiple-choice question and you have to pick the correct option. Answer with option indexes (i.e., "A", "B", "C", and "D").

A change to the environment can be (A) a toad finding a home (B) turtles eating small pellets (C) birds swimming in a pond (D) flowers poking through snow
D