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 processes occur during the life spans of all animals?  
 (A) hibernation and migration (B) growth and development (C) changing color and shedding fur (D) building nests and communication
Example Output: B

Example Input: Which best explains how nutrients get into soil?  
 (A) through exposure to air (B) by absorbing sunlight (C) through decaying matter (D) by rocks eroding
Example Output: C

Example Input: While running, leg muscles work to move leg bones, and the skin helps to  
 (A) regulate body temperature. (B) sense small changes in the heart rate. (C) transport nutrients to muscles. (D) maintain oxygen levels in the blood.
Example Output:
A