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: soil is formed by rocks eroding, Fact2: Examples of such rock include sandstone and shale ., Question: What forms soil? (A) Earthworms (B) single-celled organisms (C) an external framework (D) space travel (E) most organisms (F) sandstone eroding (G) water freezing (H) ice forming
A:
F