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").
Q: Fact1: Mutations are essential for evolution to occur., Fact2: Mutations are changes in the genetic material., Question: Changes in what are essential for evolution to occur. (A) color of leaves (B) genetic material (C) learned behavior (D) synthetic material (E) the body's largest organ (F) acquired characteristics (G) sensory neurons (H) Most plants
A:
B