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: Which is likely to provide an undesired acquired characteristic for an organism? (A) a light scratch on its leg (B) learning to leave the nest (C) finding a potential mate (D) dipping a foot in magma
Example Output: D

Example Input: What displays the movement of electrons from the base atoms? (A) venus (B) mercury (C) plasma star (D) pluto
Example Output: C

Example Input: A product of what can travel through a vacuum? (A) Rigel (B) oil well (C) volcano (D) iceberg
Example Output:
A