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.

Example 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.
Example Output: D

Example Input: Campers shouted toward a canyon wall. What characteristic of sound best explains why the campers heard an echo?  
 (A) Sound waves traveled slowly down the canyon. (B) Sound waves were absorbed by the canyon wall. (C) Sound waves reflected off the canyon wall. (D) Sound waves were refracted around the canyon.
Example Output: C

Example Input: Alisha's teacher glued a needle to a piece of cork so that the needle would float. Then he used a magnet to magnetize the needle. When the needle was placed in a bowl of water, it turned to point north. Which best describes the reason that the needle pointed north?  
 (A) The cork must also have been magnetized. (B) The magnetic field of Earth affected the needle. (C) The magnetic current in the bowl of water affected the needle. (D) The teacher must have placed the magnet to the south of the bowl.
Example Output:
B