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 Sun is classified as  
 (A) an organism (B) a decomposer (C) a star (D) a planet
[EX A]: C

[EX Q]: Carolina uses a microscope to view a soil sample taken from her backyard. Which part of the soil would she ONLY be able to see with a microscope?  
 (A) bacteria (B) grass (C) rainwater (D) rocks
[EX A]: A

[EX Q]: The news often talks about how global warming could change environmental conditions on Earth. Which best explains why global warming is such a concern?  
 (A) Glaciers will advance. (B) The sea level will rise. (C) Earthquake activity will increase. (D) The overall temperature will decrease.
[EX A]:
B