Definition: 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").
Input: Fact1: water causes refraction of light, Fact2: Refraction is the bending of a ray of light., Question: What can water cause? (A) exposure to cold (B) The bending of a ray of light (C) atmospheric depletion (D) pressure differences. (E) decreases the freezing point (F) negative impact (G) wind and erosion (H) a lot of human deaths
Output:
B