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: Rocks are classified as igneous, metamorphic, or sedimentary according to  
 (A) their color (B) their shape (C) how they formed (D) the minerals they contain

SOLUTION: C

PROBLEM: Which lists the diameter of the planets in order from smallest to largest?  
 (A) Venus, Earth, Mercury, Mars (B) Earth, Mars, Venus, Mercury (C) Mars, Mercury, Earth, Venus (D) Mercury, Mars, Venus, Earth

SOLUTION: D

PROBLEM: Which part of digestion is mainly a chemical change?  
 (A) Teeth break food into small pieces. (B) Throat muscles push food toward the stomach. (C) Stomach acids dissolve food into nutrients. (D) Intestinal cells transport nutrients into the blood.

SOLUTION:
C