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: Behaviors that improve fitness increase through natural selection., Fact2: Natural selection is differential reproduction., Question: Behaviors that improve fitness increase through (A) differential reproduction (B) produce offspring (C) biological diversity (D) metabolic reaction (E) recovery time from fatigue (F) characteristics (G) barks and snarls (H) members of their own species
Output:
A