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.

[EX Q]: The moon goes through phases as it revolves around Earth. During which phase of the moon would it be possible for a solar eclipse to occur?  
 (A) new moon (B) full moon (C) waning (D) waxing
[EX A]: A

[EX Q]: Which illness is always caused by an infection?  
 (A) a heart attack (B) a broken bone (C) influenza (D) cancer
[EX A]: C

[EX Q]: Spider webs help spiders  
 (A) avoid predators. (B) capture food. (C) stay dry. (D) keep warm.
[EX A]:
B