Detailed 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").
Q: Fact1: Population size influences the chances of a species surviving., Fact2: Economic migration affects the population size., Question: What influences the chances of a species surviving? (A) light energy (B) migration (C) plate tectonics (D) cell division (E) animals (F) temperature (G) environment (H) erosion
A:
B