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: Energy enters ecosystems in the form of sunlight or chemical compounds., Fact2: An ecosystem includes the organisms and their habitat., Question: what does energy enter in the form of sunlight or chemical compounds? (A) Generating heat (B) volume (C) colors of the spectrum (D) organisms and their habitat (E) density (F) Transfers energy (G) gravity (H) it helps plants in growing
Output:
D