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:
Which of the following correctly lists the organizational hierarchy of organisms from simplest to most complex?  
 (A) cells, organs, tissues, organ systems, organisms (B) cells, tissues, organs, organ systems, organisms (C) tissues, cells, organs, organ systems, organisms (D) tissues, organs, cells, organ systems, organisms

Ex Output:
B


Ex Input:
Which type of organism is the best at fixing nitrogen?  
 (A) bacteria (B) fungi (C) protists (D) animals

Ex Output:
A


Ex Input:
Marshall learned that plants need a substance from the air to make their own food. What does a plant take from the air in the presence of sunlight?  
 (A) carbon dioxide (B) hydrogen (C) nitrogen (D) oxygen

Ex Output:

A