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: a car engine usually converts gasoline into motion and heat through combustion, Fact2: Oxygen acts as an aid to combustion., Question: What acts as an aid to a car engine converting gasoline into motion and heat? (A) Energy. (B) oxygen (C) nitrogen (D) helium (E) argon (F) energy (G) burning (H) sugar
B