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: Northern countries have extensive erosion due to (A) glacial liquification (B) cola mining (C) more frequent tornadoes (D) meteors

Output: A


Input: Consider Input: A tone is made when a hammer makes contact with (A) a waterfall (B) air (C) an solid object (D) a log

Output: C


Input: Consider Input: Food is a source of energy for what? (A) anteaters (B) sand (C) water (D) plastic


Output: A