You are given a science question (hard-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:
The classification of some organisms has changed. Which new process is used to reclassify organisms?  
 (A) Organisms are now given Latin-based scientific names. (B) Structures are now examined at the molecular level. (C) Organisms are now divided into three kingdoms. (D) Structures are now used to classify organisms.

Ex Output:
B


Ex Input:
A bicycle is traveling at 3 meters per second (m/s). The rider applies the brakes and stops the bicycle in 3 seconds. What is the average rate of acceleration of the bicycle during this time?  
 (A) -1 m/s^2 (B) -6 m/s^2 (C) 3 m/s^2 (D) 9 m/s^2

Ex Output:
A


Ex Input:
The length of time between night and day on Earth varies throughout the year. This time variance is explained primarily by  
 (A) the position of the Sun. (B) the position of the Moon. (C) Earth's angle of tilt (D) Earth's distance from the Sun

Ex Output:

C