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: Which of these statements about nonrenewable resources is true?
(A) They are inexpensive. (B) They help keep the air clean. (C) They can take millions of years to form. (D) They are used because they are easily removed from the ground.

Output: C

Input: Consider Input: Why does the leaf of a plant look green?
(A) Because it absorbs green light (B) Because it reflects green light (C) Because it absorbs only yellow and blue light (D) Because it reflects a mixture of yellow and blue light

Output: B

Input: Consider Input: A student mixes salt and water in a beaker to form a solution. What properties of the substances would allow the student to then separate the components?
(A) densities (B) particle sizes (C) boiling points (D) electrical conductivity
Output: C