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: Which two protein molecules are essential for muscle contraction and relaxation?  
 (A) actin and myosin (B) collagen and tubulin (C) hemoglobin and myoglobin (D) amylase and polymerase
Example Output: A

Example Input: If you took all of the atoms out of a chair, what would be left?  
 (A) The chair would still be there, but it would weigh less. (B) The chair would be exactly the same as it was before. (C) There would be nothing left of the chair. (D) Only a pool of liquid would be left on the floor.
Example Output: C

Example Input: Which mixture can be easily separated by adding water and pouring it through a coffee filter?  
 (A) sugar and salt (B) salt and sand (C) sugar and baking soda (D) iron filings and sand
Example Output:
B