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").

[EX Q]: Fact1: cell division often causes growth, Fact2: Mitosis is cell division., Question: What often causes growth? (A) exercise (B) hormones (C) Atrophy (D) collagen (E) Earthworms (F) Apoptosis (G) Necrosis (H) Mitosis
[EX A]: H

[EX Q]: Fact1: water causes refraction of light, Fact2: Halos are produced by the refraction of light., Question: What causes halos? (A) germs (B) Pacific (C) solutes (D) water (E) storms (F) glass (G) algae (H) the sun
[EX A]: D

[EX Q]: Fact1: volcanic ash in the atmosphere decreases the temperature by blocking the sun, Fact2: Atmosphere is the air around an object in space., Question: How does volcanic ash in the air around the earth decrease the temperature? (A) mild heating process (B) blocking the sun (C) magnifying the light (D) heated by the sun (E) friction (F) after the snow melts (G) leaving the atmosphere (H) solidifying in the air
[EX A]:
B