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 climates has cold winters and hot summers?  
 (A) polar (B) subtropical (C) temperate (D) tropical
Example Output: C

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: Which of these is the most serious impact to an ecosystem after a tornado?  
 (A) an increase in biodiversity (B) soil erosion along with water pollution (C) the growth of plants in newly cleared areas (D) animals relocating to different habitats
Example Output:
B