Definition: 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: All chemical reactions require activation energy to get started., Fact2: Activation energy is required to overcome the energy barrier., Question: overcoming the energy barrier starts a what (A) chemical reaction (B) contraction (C) Movement of an air mass (D) expansion (E) metabolic reaction (F) energy storage (G) increased body strength (H) oxidation reaction
Output:
A