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 the following is the best observation of the refraction of light?  
 (A) Looking at oneself in a mirror (B) Looking at a shadow of an object (C) Viewing an object through an open window (D) Viewing an object partially in water

Output: D


Input: Consider Input: Which difference between water and ice results in ice floating on cold water?  
 (A) heat (B) shape (C) density (D) volume

Output: C


Input: Consider Input: Which mineral has six-sided transparent crystals that will scratch glass?  
 (A) sulfur (B) quartz (C) calcite (D) feldspar


Output: B