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 Input:
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 Output:
A


Ex Input:
Which involves the greatest variety of cell types?  
 (A) a tissue (B) an organ (C) an organ system (D) an organism

Ex Output:
D


Ex Input:
Which activity is a good health habit?  
 (A) drinking alcohol (B) exercising regularly (C) sleeping only 5 hours daily (D) smoking cigarettes

Ex Output:

B