instruction:
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.
question:
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
answer:
C


question:
An object such as a hammer weighs less on the Moon than on Earth. This is because the Moon has a  
 (A) thinner atmosphere than Earth. (B) smaller diameter than Earth. (C) stronger magnetic field than Earth. (D) lower mass than Earth.
answer:
D


question:
In the solar system, moons orbit planets. Which of these do planets orbit?  
 (A) the Sun (B) Halley's comet (C) the asteroid belt (D) a black hole
answer:

A