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: Forests are a natural store of carbon., Question: Forests naturally keep what? (A) ants (B) fish (C) carbon (D) ferns (E) firs (F) rainfall (G) heat (H) protected
A:
C