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 laser is used for producing light, Fact2: Light reveals what lies hidden in darkness., Question: What can be used to reveal what lies hidden in darkness? (A) A laser (B) Night (C) photons (D) energy (E) Electrical (F) Blackness (G) heat (H) Hidden health issues
Output:
A