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.

Example Input: Two atoms of oxygen combine to form pure oxygen gas. What is the electrical charge of the O_{2} molecules?  
 (A) positive (B) negative (C) neutral (D) variable
Example Output: C

Example Input: Which is the best evidence for the theory of continental drift?  
 (A) the appearance of volcanoes at the boundaries where plates collide (B) earthquakes at boundaries where one plate slides past another (C) cases where a species exists in only one isolated place (D) fossils of the same species found on widely separated continents
Example Output: D

Example Input: The fur of an arctic fox turns from brown to white as winter approaches. This is an example of  
 (A) camouflage (B) hibernation (C) migration (D) movement
Example Output:
A