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: Nerves all have (A) microscopic parts (B) short arms (C) viable organs (D) liver transplants
Example Output: A

Example Input: Which of the following can be found on the moon? (A) Non-volcanic Mountains (B) Life-filled Oceans (C) Volcanic Mountains (D) Multiple Land Masses
Example Output: A

Example Input: What is the most likely to be an effect of acid rain on an aquatic environment? (A) decrease in plant life (B) increase in fish population (C) increase in plant growth (D) cleaner and clearer water
Example Output:
A