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 object is best used to demonstrate the bending of light as it passes through a substance?  
 (A) convex lens (B) flat mirror (C) opaque rod (D) concave mirror
Example Output: A

Example Input: The engineering team that is designing a scientific research station on the Arctic permafrost has to provide the station with energy for cooking, heating, and lighting. Considering the fragile environment and other conditions there, the best choice is probably to  
 (A) build a wind turbine. (B) have fuel trucked in. (C) have a pipeline built. (D) build a solar collector.
Example Output: A

Example Input: A scientist discovered a way to turn plant material into fuel. This more cleanly burning fuel can be used in cars. How do people most likely benefit from turning plant material into fuel?  
 (A) Cars are safer to drive. (B) Farmers grow more plants. (C) The amount of air pollution is reduced. (D) The number of cars around the world increases.
Example Output:
C