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: Amphibians have permeable skin that easily absorbs substances from the environment., Fact2: All frogs are amphibians., Question: What has permeable skin? (A) goats (B) alligators (C) animals (D) apples (E) frogs (F) sharks (G) humans (H) snakes
[EX A]: E

[EX Q]: Fact1: some animals' fur grows thicker for staying warm in the winter, Fact2: During winter, their hollow fur absorbs much heat as they sun themselves., Question: hollow fur keeps animals what (A) fats (B) camouflaged (C) safe (D) warm (E) cooled (F) liquid (G) live (H) from drowning
[EX A]: D

[EX Q]: Fact1: using a car causes pollution, Fact2: Air pollution Air pollution is a major threat to health., Question: What can be a major threat to health? (A) bicycling (B) using a car (C) smoking (D) skateboarding (E) viruses (F) Dehydration (G) influenza (H) doctors
[EX A]:
B