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:
Large amounts of industrial gases are released into the atmosphere every day. What happens to those gases?  
 (A) They are broken down by ultraviolet light from the Sun. (B) They are converted into nitrogen and oxygen. (C) They rise through the atmosphere and go into outer space. (D) They remain in the atmosphere for long periods of time.

Ex Output:
D


Ex Input:
A bright object with a long tail of glowing gases is in orbit around the Sun. This object is most likely  
 (A) a planet (B) a star (C) an asteroid (D) a comet

Ex Output:
D


Ex Input:
Professor Walden studies genetics at a local university. She believes that she has discovered information that contradicts a widely accepted theory. As a scientist and leader in the study of genetics, which action should she take?  
 (A) Announce to the world that her theory is better than the old theory. (B) Call the news media and tell them about her new theory. (C) Challenge the old theory with scientific evidence. (D) Request that the old theory be banned.

Ex Output:

C