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 life processes occur in both plants and humans?  
 (A) growing and reproducing (B) germinating and making food (C) growing and making food (D) germinating and reproducing
Example Output: A

Example Input: Which of the following would be more likely to pollute a river?  
 (A) allowing beavers to build a dam (B) spreading fertilizer near the river (C) mowing the grass on the river bank (D) fishing from a bridge over the river
Example Output: B

Example Input: When blood that is high in carbon dioxide exits the heart, it immediately enters which body system?  
 (A) nervous (B) respiratory (C) digestive (D) muscular
Example Output:
B