You are given a science question (easy-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

Ex Input:
A scientific guess about the cause and effect of an event is called  
 (A) a variable. (B) a theory. (C) a hypothesis. (D) an observation.

Ex Output:
C


Ex Input:
During a biochemical reaction, pyruvate (C3H4O3) is converted into carbon dioxide (CO2) and water (H2O). In what cellular organelle does this biochemical reaction occur?  
 (A) nucleus (B) cytoplasm (C) mitochondria (D) endoplasmic reticulum

Ex Output:
C


Ex Input:
Arctic areas are covered with snow and ice for much of the year. Which color rabbits would be safest from foxes there?  
 (A) grey (B) black (C) white (D) brown

Ex Output:

C