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: Mutation creates new genetic variation in a gene pool., Fact2: Genetic variation is the basis for natural selection., Question: what is the basis for natural selection? (A) hydrogen (B) root growth (C) weathering (D) animals (E) artificial intelligence (F) mutation (G) trees (H) competition
F