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:
Which of the following Earth layers has the greatest density?  
 (A) crust (B) mantle (C) inner core (D) outer core

Ex Output:
C


Ex Input:
Cells take in food for energy. The part of the cell that aids in digestion of the food is the lysosome. What is the main role of lysosomes in the process of food digestion?  
 (A) building proteins (B) breaking down wastes (C) controlling the activities of the cell (D) converting energy from one form into another

Ex Output:
B


Ex Input:
The weather forecast says a heavy snowstorm is coming later today. Which weather observation is likely just before the snow?  
 (A) clear sky (B) thick grey clouds (C) small white clouds (D) warm temperature

Ex Output:

B