Q: 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").
Fact1: chemical weathering causes iron in rock to oxidize, Fact2: Low rainfall means slow chemical weathering of rock., Question: What can lead to oxidation of iron in rock? (A) heat energy (B) low rainfall (C) flow of electrons (D) permineralization (E) fossil fuels (F) harmful substances (G) boiling (H) evaporation
A:
B