Instructions: 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: Evolution occurs by a process called natural selection., Fact2: Evolution is a sequence of variation and selection., Question: what produces variation? (A) animals (B) evolution (C) pollen (D) environment (E) a doorbell (F) movement (G) seasons (H) competition
Output:
B