Given the task definition and input, reply with output. 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 fire requires oxygen to burn, Fact2: Oxygen has eight protons and eight electrons., Question: What does a fire require to burn? (A) A transportation fuel (B) Something with exactly 2 protons (C) chemical to mechanical energy (D) Something with exactly eight protons (E) Something with exactly 1 proton (F) Burning fuel and air (G) igniting fuel and oxidiser (H) Something with 7 protons
D