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: The excessive use of nitrogen-based fertilizers causes runoff that increases the nitrogen content of lakes and bays. These nitrogen compounds directly affect the aquatic ecosystems by  
 (A) interfering with the water cycle. (B) decreasing the predator population. (C) increasing the rate of algae growth. (D) causing aquatic animals to grow larger.
Example Output: C

Example Input: In Maryland, most bears have thick, dark fur. Which statement best explains how dark fur helps bears survive in the forests of Maryland?  
 (A) Dark fur is lightweight. (B) Dark fur scares enemies. (C) Dark fur helps bears hide. (D) Dark fur keeps bears cool.
Example Output: C

Example Input: When mining for coal, a mining company removes the plants and layers of soil and rock above the coal deposit, and takes the coal. When the operation is complete, the mining company returns soil and rock, covers it with a layer of topsoil, and plants trees and grass. The trees and grass help to  
 (A) prevent a collapse of the underlying sediment. (B) limit the types of pollutants that can enter the soil. (C) increase water absorption by the replaced sediments. (D) reduce soil erosion and provide new habitat for animals.
Example Output:
D