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: According to cell classification, prokaryotic cells are separated from eukaryotic cells. Which feature is often used to distinguish prokaryotic cells from eukaryotic cells?  
 (A) life processes (B) size differences (C) plasma membranes (D) energy molecules
Example Output: B

Example Input: The weight of an object can change even when the mass stays the same. Which statement correctly identifies a relationship between mass and weight?  
 (A) The weight of an object depends on its mass and its volume. (B) Gravity affects the weight of an object but not its mass. (C) The mass of an object depends on its weight and size. (D) Magnetic fields can affect mass but not weight.
Example Output: B

Example Input: Farmers plant fruit trees in an area that was once a grassy meadow. Which will most likely happen to the rabbits living in the meadow?  
 (A) They will learn to eat fruit. (B) They will learn to climb trees. (C) The number of their young will increase. (D) The size of their population will decrease.
Example Output:
D