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: Which is the best example of something that has kinetic energy?  
 (A) a rock sitting at the top of a steep hill (B) a tennis ball rolling across the court (C) a picture hanging on the wall (D) a piece of wood before it is burned
Example Output: B

Example Input: Greenhouse gases in the atmosphere absorb infrared radiation from Earth's surface and re-radiates some of it back to Earth. Which of these gases have the most significant impact on the temperature of Earth's atmosphere?  
 (A) nitrogen and argon (B) oxygen and sulfur dioxide (C) carbon dioxide and water vapor (D) hydrochloric acid and hydrogen
Example Output: C

Example Input: Eduardo saw some cats living in an alley. Which of these does a cat need to survive?  
 (A) grass to sleep in (B) large trees to climb (C) predators to chase it (D) small animals to eat
Example Output:
D