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 example would result in new cells that are most different from the parent cells?  
 (A) yeast cells splitting into new cells (B) bacteria cells dividing into new cells (C) skin cells dividing to produce more skin cells (D) sperm and egg cells uniting to produce fertilized egg cells
Example Output: D

Example Input: What has occurred when bubbles form in a liquid that is being heated?  
 (A) Oxygen is absorbed from the air. (B) Heat is radiating in the liquid. (C) The boiling point has been reached. (D) Molecular stability in the liquid is increasing.
Example Output: C

Example Input: Scientists have categorized trees based on whether they keep or lose their leaves each year. Another logical way to categorize trees is based on the  
 (A) types of nutrients needed to grow. (B) amount of oxygen that is released into the air. (C) color of leaves that are produced. (D) type of fruit that is produced.
Example Output:
D