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: a compass is used to navigate oceans, Fact2: And to the east is the Atlantic Ocean., Question: what is a compass used to navigate? (A) density (B) lamphreys (C) marine (D) outer space (E) their speed (F) Antarctica (G) non-magnetic planets (H) the Atlantic

A: H
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Q: Fact1: a glacier causes mechanical weathering, Fact2: Largest of the glacier-formed lakes is Karakul., Question: What can be formed by mechanical weathering? (A) NaCl (B) white (C) rock (D) tube (E) soils (F) Roads (G) Lakes (H) sand

A: G
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Q: Fact1: burning wood is used to produce heat, Fact2: Air pollution is created by burning., Question: What causes air pollution? (A) Smoking (B) cigarettes (C) producing heat (D) Electrical energy (E) oxygen (F) chemical reaction (G) wind turbines (H) clouds

A:
C
****