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: sound can be used for communication by animals, Fact2: Sounds are vibrations in air., Question: Vibrations in air can be used for what by animals? (A) activation energy (B) communication (C) Something to move (D) sleeping (E) sustenance (F) Heart rate (G) food and shelter (H) tasting
B