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: using a gasoline engine requires burning gasoline, Fact2: And, of course, burning of gasoline produces toxic carbon monoxide., Question: Toxic carbon monoxide is produced by what? (A) gasoline engines (B) Electric generators (C) electric cars (D) electricity (E) solar panels (F) cigarettes (G) an engine (H) ionization
A:
A