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: Unlike trees in the forest or a pond full of fish, metal is only available until (A) it is depleted for good (B) it is found on catfish scales (C) it becomes necessary to conduct electricity long distances (D) it is used to make diamond rings
Example Output: A

Example Input: What requires photosynthesis to grow? (A) hills (B) planets (C) flora (D) people
Example Output:
C