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: Fuel is burned inside the engine., Question: Carbon monoxide, a product of furnaces and engines, is a: (A) acid (B) CO2 (C) kill (D) harm (E) gas (F) form (G) CO 2 (H) HPV
E