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 body of a fish is covered by scales for  
 (A) decoration. (B) protection. (C) coloration. (D) reproduction.

Ex Output:
B


Ex Input:
Which of the following is an observation about grasshoppers that a science class could have made on their nature walk?  
 (A) The grasshoppers will live longest in a container filled with plants. (B) The grasshoppers are green with long back legs and antennae. (C) The grasshoppers will probably eat more grass than tree leaves. (D) The grasshoppers all hatched from eggs laid the year before.

Ex Output:
B


Ex Input:
Energy companies often produce electricity from a variety of sources. Using which resource would improve air quality the most?  
 (A) oil (B) gas (C) coal (D) wind

Ex Output:

D