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: In an accurate diagram of the solar system, which object would be shown closest to Earth?  
 (A) the Moon (B) the asteroid belt (C) Mars (D) Saturn
Example Output: A

Example Input: A student conducts an investigation. In order to make a valid conclusion, she must  
 (A) have a testable hypothesis. (B) place the data in a graph. (C) use the best technology. (D) test multiple variables.
Example Output: A

Example Input: Which best explains why population growth can result in water shortages and rationing in certain areas?  
 (A) Aquifers recharge slowly. (B) Lake water is reserved for recreation. (C) Increasing biomass decreases evaporation rates. (D) Tall buildings impede the development of rain clouds.
Example Output:
A