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 condition in bees called "colony collapse disorder" occurs when worker bees leave the hive to collect nectar and never return. How would a decline in the bee population most likely affect a farm ecosystem?  
 (A) There would be a decrease in soil thickness. (B) There would be a decline in fruit production. (C) There would be an increase in plant diseases. (D) There would be an increase in insect pest populations.
Example Output: B

Example Input: Which illness is always caused by an infection?  
 (A) a heart attack (B) a broken bone (C) influenza (D) cancer
Example Output: C

Example Input: What happens to a moist air mass as it moves upward in the atmosphere?  
 (A) It becomes warmer and forms clouds. (B) It becomes cooler and forms clouds. (C) Its temperature remains the same. (D) Its temperature varies greatly.
Example Output:
B