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:
What is the main function of red blood cells?  
 (A) To fight disease in the body (B) To carry oxygen to all parts of the body (C) To remove carbon monoxide from all parts of the body (D) To produce materials which cause the blood to clot.

Ex Output:
B


Ex Input:
A boy pulls a sweater off over his head. His hair is attracted to the sweater due to  
 (A) a magnetic force (B) a heat transfer (C) a chemical change (D) an electrical charge

Ex Output:
D


Ex Input:
A student places a ball on the ground and kicks it. The ball moves along the ground. Why does the ball move?  
 (A) The kick decreases the weight of the ball. (B) The kick applies a contact force to the ball. (C) The kick decreases the force of gravity acting on the ball. (D) The kick removes friction between the ball and the ground.

Ex Output:

B