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.

Ex 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

Ex Output:
D


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

Ex Output:
B


Ex Input:
A researcher found shark fossils on top of a mountain. This evidence suggests which of the following about this region?  
 (A) It was once below a waterfall. (B) It was once part of a riverbed. (C) It was once covered by an ocean. (D) It was once near a freshwater lake.

Ex Output:

C