Given the task definition and input, reply with output. 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: a cactus stem is used for storing water, Fact2: A striking cactus plant from Mexico., Question: What can be used for storing water? (A) marshes and swamps (B) Something made from fermented ricce (C) Something that grows in Mexico (D) plankton and nonliving organic (E) roots and shoots (F) evaporative cooling (G) A transportation fuel (H) that material's properties
C