Teacher: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").
Teacher: Now, understand the problem? Solve this instance: Fact1: most canyons are formed by flowing rivers through erosion over long periods of time, Fact2: Rivers and glaciers are made of water., Question: Flowing water forms most canyons through erosion over what? (A) movement of tectonic plates (B) dry streambeds (C) long periods of time (D) Physical weathering (E) Time and energy (F) short periods of time (G) massive damage (H) calving glaciers
Student:
C