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 teacher breaks a bar of pure copper into two different sized pieces. Which is the most likely difference between the two pieces?  
 (A) mass (B) texture (C) boiling point (D) melting point

Ex Output:
A


Ex Input:
A bird eats a brightly-colored insect that tastes bad. The bird avoids preying on this type of insect again. This example is best described as  
 (A) a physical characteristic. (B) a learned behavior. (C) an inherited behavior. (D) an adaptation.

Ex Output:
B


Ex Input:
Which function requires the muscular, skeletal, and nervous systems to work together?  
 (A) movement of appendages (B) completion of blood circulation (C) absorption of nutrients (D) regulation of hormones

Ex Output:

A