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: What is the complementary base to cytosine in DNA?  
 (A) uracil (B) thymine (C) guanine (D) adenine
Example Output: C

Example Input: Because water can hold a large amount of heat, which effect do oceans have on nearby land areas?  
 (A) They prevent rapid extreme temperature changes. (B) They form high-pressure areas that cause magma currents. (C) They provide the energy that triggers volcanic events. (D) They lower the freezing point of fresh water.
Example Output: A

Example Input: A student is investigating a light bulb that saves energy and can last up to 10 times longer than other bulbs. Other than saving energy, which is another benefit of using these light bulbs?  
 (A) Drinking water stays clean. (B) Less trash is put in landfills. (C) More nutrients are added to the soil. (D) Fewer chemicals get into the food supply.
Example Output:
B