Q: 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: cellular respiration is when a cell converts from oxygen and carbohydrates into carbon dioxide, water, and energy, Fact2: Cellular respiration involves a series of enzyme-mediated reactions., Question: what is it when a cell converts from oxygen and carbohydrates into carbon dioxide, water, and energy? (A) A transportation fuel (B) extremely important (C) a hemisphere is tilted away from the sun (D) series of enzyme-mediated reactions (E) production of energy (F) the most widely used biofuel (G) chemical messengers (H) it helps plants in growing
A:
D