You are given a science question (hard-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 source of data about Nevada resources is likely to be most current and reliable?  
 (A) a science encyclopedia (B) an article in a local newspaper (C) a government-maintained website (D) a student's classroom presentation
Example Output: C

Example Input: Which of these best describes a change that is physical?  
 (A) yarn being knitted into a sweater (B) the engine from a tractor being started (C) the metal on a bicycle forming rust (D) grass capturing the energy from sunlight
Example Output: A

Example Input: The composition of soil influences the soil's ability to retain and transmit water and air. What soil type would be best for planting a productive garden?  
 (A) Sandy soils because they provide high silica content. (B) Loamy soils because they contain sand and clay. (C) Slightly rocky soils because they provide needed minerals. (D) Clay soils because they are heavy soils and retain water.
Example Output:
B