You will be given a definition of a task first, then some input of the task.
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: Also pyrite within the altered wall rock is oxidized to limonite, geothite and hematite., Question: chemical weathering causes what to change to limonite (A) pyrite (B) growth (C) Collagen (D) fibrous (E) cellulose (F) soil (G) cracks (H) calcite
Output:
A