In this task, you are given a multiple-choice question and you have to pick the correct option. Answer with option indexes (i.e., "A", "B", "C", and "D").

Example Input: A learned characteristic could be (A) Eye color (B) a cartwheel (C) freckles (D) Hair color
Example Output: B

Example Input: An echo is produced by what type of reflection of sound source? (A) Direct (B) Distant (C) Varied (D) Single
Example Output: D

Example Input: Birds reproduce using (A) live birth (B) cloning. (C) eggs (D) mitosis
Example Output:
C