Detailed Instructions: 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").
Q: Fact1: gravity pulls objects towards planets, Fact2: Because of gravitation, objects that are on or near the earth are pulled toward it., Question: What causes water to stay on earth's surface? (A) Clouds (B) Planets (C) rainfall (D) friction (E) Gravity (F) sun's heat (G) Dirt (H) forces
A:
E