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: Carbon may be stored in sedimentary rock for millions of years., Fact2: Limestone is a type of sedimentary rock., Question: what can carbon be stored in for millions of years? (A) limestone (B) fossil fuels (C) hydrocarbons (D) graptolites (E) fish (F) humans (G) h2o (H) layers of fat
A:
A