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 of the following actions will increase the gravitational force between two masses, m_{1} and m_{2}, by the greatest amount?  
 (A) Halve the mass of m_{1} and halve the distance between m_{1} and m_{2}. (B) Halve the mass of m_{1} and double the distance between m_{1} and m_{2}. (C) Double the mass of m_{1} and halve the distance between m_{1} and m_{2}. (D) Double the mass of m_{1} and double the distance between m_{1} and m_{2}.
Example Output: C

Example Input: Which equation is a balanced chemical equation?  
 (A) 2NaOH + CaBr_{2} -> Ca(OH)_{2} + NaBr (B) NO + Cl_{2} -> NOCl (C) CaCO_{3} -> CaO + 2CO_{2} (D) 2AlCl_{3} + 3Mg -> 3MgCl_{2} + 2Al
Example Output: D

Example Input: Some part of Earth is being heated by the Sun at all times. If Earth absorbed all of the energy it received from the Sun, environmental conditions would change on the planet and existing ecosystems would be unsustainable. Which is a way that Earth loses energy from the Sun?  
 (A) The oceans absorb the energy. (B) Clouds reflect the energy into space. (C) Plants store the energy as chemicals. (D) The atmosphere is heated by the energy.
Example Output:
B