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").
Input: Fact1: a prism is used for refracting light, Fact2: Light seems to travel in rays or beams., Question: what is a prism used to refract? (A) focusing a lens (B) photons (C) h2o (D) glass (E) oxygen (F) rays or beams (G) our nearest star (H) an electron lens
Output:
F