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]: One important use of coal is to produce energy for homes. Coal can be burned and converted to  
 (A) wind energy. (B) nuclear energy. (C) electrical energy. (D) solar energy.
[EX A]: C

[EX Q]: In an accurate diagram of the solar system, which object would be shown closest to Earth?  
 (A) the Moon (B) the asteroid belt (C) Mars (D) Saturn
[EX A]: A

[EX Q]: What is the name of the author who proposed natural selection as the mechanism of evolution?  
 (A) Mendel (B) Darwin (C) Lamarck (D) Hardy-Weinberg
[EX A]:
B