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: uneven heating of the Earth 's surface cause wind, Fact2: Wind is a movement of air, and air is invisible., Question: Uneven heating of the Earth 's surface causes a movement of what? (A) wind (B) light (C) air (D) soil (E) sand (F) asteroids (G) cookies (H) Aves
Output:
C