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.

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

Output: D


Input: Consider Input: The pull of gravity from Earth has the greatest effect on  
 (A) comets. (B) the Sun. (C) asteroids. (D) the Moon.

Output: D


Input: Consider Input: Which of the following shows the correct sequence of inventions?  
 (A) printing press -> microscope -> telephone (B) television -> automobile -> microwave (C) airplane -> microphone -> radio (D) Doppler radar -> microphone -> telescope


Output: A