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: One method of heat distribution is a baseboard forced hot water system. A baseboard system carries hot water through a pipe that passes through many small, flat plates called fins. What is the purpose of these fins?  
 (A) to dissipate the heat of the hot water flowing through the pipe (B) to prevent the baseboard from coming in contact with hot surfaces (C) to replace the heated air leaving the system with cold air (D) to prevent dust and other particles from entering the baseboard
Example Output: A

Example Input: The moon goes through phases as it revolves around Earth. During which phase of the moon would it be possible for a solar eclipse to occur?  
 (A) new moon (B) full moon (C) waning (D) waxing
Example Output: A

Example Input: When mountains are formed, there is an interaction between areas of Earth. Which two will interact and result in the formation of mountains?  
 (A) hydrosphere and biosphere (B) troposphere and ionosphere (C) hydrosphere and lithosphere (D) asthenosphere and lithosphere
Example Output:
D