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: In gym class a student kicks a soccer ball high into the air. As the ball goes upward, which type of energy is increasing?  
 (A) kinetic energy (B) thermal energy (C) potential energy (D) mechanical energy
Example Output: C

Example Input: Which human organ system eliminates liquid and gaseous wastes from the body?  
 (A) circulatory (B) endocrine (C) excretory (D) reproductive
Example Output: C

Example Input: Which of the following is a part of the process of sexual reproduction?  
 (A) budding (B) regeneration (C) pollination (D) fragmentation
Example Output:
C