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: Planting certain crop plants in a field causes a disruption of the natural nitrogen cycle in that field. Which outcome would this disruption most DIRECTLY cause in the field over time?  
 (A) topsoil erodes (B) soil nutrients decrease (C) desert conditions appear (D) atmospheric carbon dioxide increases
Example Output: B

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: Light travels fastest through which of the following?  
 (A) air (B) glass (C) water (D) a vacuum
Example Output:
D