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 of the following forms of energy is released or absorbed in most chemical reactions?      
 (A) light energy (B) electrical energy (C) sound energy (D) heat energy
Example Output: D

Example Input: Shale is a sedimentary rock that can be metamorphosed into slate by  
 (A) cementation. (B) chemical weathering. (C) sedimentation. (D) increased pressure.
Example Output: D

Example Input: Which scientist is best known for studying plants and animals?  
 (A) Isaac Newton (B) Albert Einstein (C) Charles Darwin (D) Nicolaus Copernicus
Example Output:
C