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: Earth 's magnetic patterns are used for finding locations by animals that migrate, Fact2: Animated maps show the birds flying along their actual migration paths., Question: Earth's magnetic patterns are used so that birds can fly along their what? (A) migrating pain (B) migration paths (C) our nearest star (D) flying schedule (E) Something to move (F) travel plans (G) important habitats (H) their hosts
Output:
B