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: a cactus stem is used for storing water, Fact2: Other animals eat cactus to get water., Question: Why do animals eat stems? (A) Animal survival (B) A transportation fuel (C) it keeps an organism warm (D) It gets more light (E) basic building blocks of life (F) Plants store liquids there (G) it needs them (H) Help plants grow
Output:
F