You will be given a definition of a task first, then some input of the task.
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: a rainbow is formed by refraction of light by separating light into all different colors, Fact2: Light rays come in through the lens., Question: A rainbow is formed by what of rays? (A) an electron microscope (B) energy of moving objects (C) heat energy (D) Solar energy (E) rain or sun shine (F) separation of colors (G) sun's heat (H) flow of electrons
Output:
F