Instructions: 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").
Input: Fact1: an automobile engine transforms chemical energy into mechanical energy, Fact2: Automobile engines have a range where they are most efficient., Question: The efficiency of an engine range is due to what? (A) Movement of an air mass (B) principals of aerodynamics (C) transportation technology (D) heat production (E) heat is produced (F) A transportation fuel (G) Inches or fractions of inches. (H) chemical to mechanical energy
Output:
H