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: Humans contribute to environmental pollution (A) by purchasing products made from recycled products (B) by switching to energy efficient appliances (C) by leaving behind refuse on public beaches (D) by frequently recycling paper and plastic
Example Output: C

Example Input: In a zoo, a polar bear exhibit will contain (A) salt (B) cacti (C) strong fans (D) sand
Example Output: C

Example Input: Marshmallows plus ____ technically make a different substance. (A) steak (B) cookies (C) chocolate (D) fire
Example Output:
D