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 of these will best separate a saltwater solution?  
 (A) using a paper filtering system (B) using chromatography (C) allowing the salt to settle (D) allowing the water to evaporate

SOLUTION: D

PROBLEM: Which of these could cause water vapor to condense into rain droplets?  
 (A) sunlight warming the surface of oceans (B) air rising into colder regions of the atmosphere (C) lightning heating the air in the atmosphere (D) winds blowing along the surface of the ground

SOLUTION:
B