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: What did some ancient societies use to reflect light? (A) wood (B) plants (C) clothing (D) rocks
Example Output: D

Example Input: which of these people would be most susceptible to disease? (A) a person with a healthy white blood cell (B) a person with optimal conditions (C) a person with a weak white blood cell (D) an athlete with a clean bill of health
Example Output: C

Example Input: A boy wants to feed a gecko so he gives it (A) waxworms (B) dog food (C) chickens (D) markers
Example Output:
A