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:
Proxima Centauri is the closest star to the Sun. Which units do astronomers most often use for the distance between Earth and Proxima Centauri?  
 (A) miles (B) meters (C) light years (D) astronomical units

Ex Output:
C


Ex Input:
Alex looked at an electric toothbrush that had a plug with three metal prongs. Why are these prongs made out of metal?  
 (A) Metal doesn't get hot and melt when you plug it into the outlet. (B) Metal is strong and is less likely to break when you plug it into the outlet. (C) Metal is an insulator and prevents shocks when you plug it into the outlet. (D) Metal is a conductor and completes a circuit when you plug it into the outlet.

Ex Output:
D


Ex Input:
Which organisms break down dead matter and recycle nutrients back into the ecosystem?  
 (A) grasses and trees (B) rabbits and deer (C) lions and alligators (D) mushrooms and bacteria

Ex Output:

D