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: The systems of the human body work together. Which system works with the skeletal system by pulling on the bones to create movement?  
 (A) digestive (B) circulatory (C) muscular (D) nervous
Example Output: C

Example Input: Which involves the greatest variety of cell types?  
 (A) a tissue (B) an organ (C) an organ system (D) an organism
Example Output: D

Example Input: Which change would most likely cause deer to die or leave a woodland?  
 (A) a forest fire (B) a rainstorm (C) a snow storm (D) a sinkhole
Example Output:
A