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: Photosynthesis is the process that converts carbon dioxide and water into  
 (A) carbon and oxygen. (B) sugar and hydrogen. (C) sugar and oxygen. (D) nitrogen and carbon.
Example Output: C

Example Input: In a lab investigation, a student notes that two metal blocks have the same mass. Based on this observation, if the two blocks were put on opposite sides of a balance, they would best represent  
 (A) balanced forces. (B) unbalanced forces. (C) equal and opposite reactions. (D) objects in motion.
Example Output: A

Example Input: Which part of a sunflower plant absorbs water and nutrients?  
 (A) Roots (B) Stems (C) Leaves (D) Flowers
Example Output:
A