Given the task definition and input, reply with output. In this task, you are given two facts, and a multiple-choice question. Based on the given facts, answer the question with index of the correct option (e.g, "A").

Fact1: Playing is one way mammals and other animals learn how to behave., Fact2: Second stage, learn how to behave assertively., Question: How do animals learn how to be assertive? (A) lectures from their parent (B) instinct (C) Movement (D) playing (E) being killed (F) ligt (G) sweating (H) exercise
D