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 something is in an ecosystem, it could be (A) invisible (B) vacuum of space (C) lacking life (D) alien
Example Output: C

Example Input: What does a seismograph measure? (A) the motion produced by underground collisions (B) the quaking of a man in fear (C) how strong the earth quakes beneath a stampeding herd (D) how strong waves can break plates
Example Output: A

Example Input: A toad would have better hiding places (A) on a house rooftop (B) in a glass bottle (C) on a forest floor (D) with a parachute skydiving
Example Output:
C