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 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: In the human body, which system functions primarily to defend the body against disease?  
 (A) digestive (B) immune (C) nervous (D) respiratory
Example Output: B

Example Input: A student is designing a model of the solar system and writing a report. She is trying to be as accurate as possible. Which statement should she include in her report?  
 (A) The distance between the Sun and Earth is measured in light years. (B) Jupiter and Uranus are considered to be terrestrial planets. (C) The asteroid belt is located between Jupiter and Saturn. (D) The orbit of Mars is similar to the orbit of Saturn.
Example Output:
D