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: A leaf is covered in mud during a landslide. After one million years, this leaf will most likely be ___.  
 (A) a fossil (B) an animal species (C) a new plant species (D) a nonrenewable fuel
Example Output: A

Example Input: Which of the following best describes a mineral?  
 (A) a solid natural material with a crystal structure (B) a material that was once living but has decayed (C) a liquid chemical used to make soil more fertile (D) a nutrient produced by plants that other organisms need
Example Output: A

Example Input: A scientist plans to investigate the nervous system of sea slugs. What should the scientist do first?  
 (A) Develop a theory about sea slugs that can be tested. (B) Go to the ocean to observe the behavior of sea slugs. (C) Obtain several sea slugs and conduct experiments with them. (D) Review the research other scientists have done on sea slugs.
Example Output:
D