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: chemical weathering causes iron in rock to oxidize, Fact2: Fe is the periodic symbol for Iron., Question: Chemical weathering causes what in rock to oxidize? (A) Fe (B) tar (C) h2o (D) H20 (E) DDT (F) Ag (G) O (H) CO2
A:
A