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.

[Q]: Which best explains how nutrients get into soil?
(A) through exposure to air (B) by absorbing sunlight (C) through decaying matter (D) by rocks eroding
[A]: C

[Q]: Which of these substances is correctly identified as a mineral?
(A) coal (B) quartz (C) granite (D) sandstone
[A]: B

[Q]: Which of these is a waste product of plant cells?
(A) minerals (B) oxygen (C) heat (D) water
[A]:
B