Detailed Instructions: 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").
Q: Fact1: Chemical bonds form when substances react with one another., Fact2: Chemical bonds vibrate., Question: what does substances reacting with one another cause? (A) density (B) forces (C) vibration (D) death (E) illness (F) earthquakes (G) Leptospirosis (H) volume
A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
C