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: the emission of sulfur dioxide causes acid rain, Fact2: It's sulfur dioxide (SO2)., Question: The emission of what causes acid rain? (A) H2O (B) smoke from food (C) Hydrogen (D) coal (E) SO2 (F) oil (G) CFCs (H) Cars
A:
E