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: Most ecosystems get energy from sunlight., Fact2: On Earth, energy from sunlight heats the atmosphere more at the equator than at the poles., Question: Most ecosystems get energy from what in the atmosphere? (A) fires (B) Sun (C) wind (D) summer (E) oxygen (F) Light (G) heat (H) H20
G