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: if a river ran through a region, what would be found close by? (A) land mass susceptible to water encroachment (B) active life coral reef (C) acid rain susceptible area (D) very active volcanic mountains
Example Output: A

Example Input: Why was my son-in-law required to add rugs or carpeting to his upstairs apartment when the ground floor wasn't? (A) So it would look good then prospective renters took a tour (B) Because they didn't want him to scratch up the wood floors. (C) Because they didn't want the downstairs renters to be as likely to complain about noise (D) Because they didn't want to pay for carpeting themselves.
Example Output: C

Example Input: Some people put metal tags on their dog's collars, because in darkness, these collars can (A) melt wax (B) reflect light (C) read books (D) stain clothes
Example Output:
B