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 units best represents the density of an object?  
 (A) kg (B) hr (C) m/s^2 (D) g/cm^3

Ex Output:
D


Ex Input:
Typically, sedimentary rocks are formed  
 (A) only in erupting volcanoes. (B) only under great pressure and high temperatures. (C) below Earth's surface as magma cools and crystallizes. (D) from materials that settle.

Ex Output:
D


Ex Input:
Which is true of scientific discoveries?  
 (A) All scientific discoveries are based solely on observation and never experimentation. (B) Sometimes scientific discoveries are made by accident, like the discovery of penicillin. (C) If a scientist cannot provide the exact time and place his or her discovery was made, it is dismissed. (D) All scientific discoveries are regulated by government agencies, like the Food and Drug Administration.

Ex Output:

B