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 of these elements is found in the greatest amount in organisms?  
 (A) carbon (B) iron (C) lead (D) neon
Example Output: A

Example Input: Research in which of these areas has the greatest impact on the environment?  
 (A) irradiating food (B) organic fertilizers (C) bacteria to clean up oil spills (D) developing larger, sweeter strawberries
Example Output: C

Example Input: What cycle is most directly affected by the combustion of fossil fuels?  
 (A) rock cycle (B) water cycle (C) carbon cycle (D) nitrogen cycle
Example Output:
C