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: The cell membrane keeps a cell from (A) replicating (B) getting lost (C) falling apart (D) running away
Example Output: C

Example Input: Sunlight transfers heat energy to (A) the star from which scorpions get their name (B) the planet named after the Roman god of sea (C) the largest star in the galaxy (D) the hottest star in the galaxy
Example Output:
B