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 experiment studying phototropism, students grew bean plants in labeled cardboard milk cartons. Afterward, the plants and soil were properly discarded. Which instruction line BEST conserves the remaining resources?  
 (A) recycle the markers, reuse the milk cartons (B) reuse the markers, discard the milk cartons (C) discard the markers, reuse the milk cartons (D) reuse the markers, recycle the milk cartons
Example Output: D

Example Input: One important use of coal is to produce energy for homes. Coal can be burned and converted to  
 (A) wind energy. (B) nuclear energy. (C) electrical energy. (D) solar energy.
Example Output: C

Example Input: During the Siberian summer, reindeer graze on young roots, fungi, grass, and other vegetation. In the cold winter months, they migrate south and rely on available, but less nutritious food, such as lichen. Increased snowfall during the entire winter in southern areas would result in reindeer having to  
 (A) return to their summer feeding area. (B) hibernate until the snows have stopped. (C) hunt for organisms such as small rodents. (D) move to other areas to compete for resources.
Example Output:
D