TASK DEFINITION: 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.
PROBLEM: The fusion reaction that fuels the Sun converts hydrogen into  
 (A) carbon. (B) iron. (C) neon. (D) helium.

SOLUTION: D

PROBLEM: Which tool would be best to use for counting the number of legs on an ant?  
 (A) ruler (B) hand lens (C) calculator (D) microscope

SOLUTION: B

PROBLEM: If the solar system were used as a model of an atom, what would the Sun most likely represent?  
 (A) an ion (B) a nucleus (C) a neutron (D) an electron

SOLUTION:
B