You will be given a definition of a task first, then some input of the task.
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").

Fact1: Carbon monoxide is a gas produced by furnaces and other devices that burn fuel., Fact2: Excessive accumulation build-up of carbon monoxide can cause suffocation., Question: What can gas furnaces cause? (A) matter vibrating (B) Pollution (C) rain (D) Stale air (E) condensation (F) emissions (G) suffocation (H) friction
Output:
G