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 dog can learn how to do something that it is taught to do, called learned behavior, such as (A) eat food when it is hungry (B) lean back and accept having nails trimmed (C) bark when it wants to (D) urinate when its bladder is full
B