Definition: 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").
Input: Fact1: most canyons are formed by flowing rivers through erosion over long periods of time, Fact2: Rivers, rainwater, well water and most lakes contain fresh water., Question: What are canyons formed by? (A) clouds (B) stars (C) erosion (D) loose soil (E) wind (F) ice wedging (G) rainwater (H) calcite
Output:
G