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").

Input: Consider Input: if the surface of our planet is different after a while, what could have happened? (A) the surface eroded on its own (B) all of these (C) there were natural occurrences (D) man has damaged the surface

Output: B


Input: Consider Input: A learned behavior is exhibited when a human displays that they can: (A) squinting in bright light (B) digesting food in the stomach (C) change a car tire (D) inhaling and exhaling during sleep

Output: C


Input: Consider Input: The lungs give O2 to the (A) bloodstream (B) neighbor (C) ozone (D) poor


Output: A