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.

Input: Consider Input: Electron transport in mitochondria results in a chemiosmotic gradient of which particle across the mitochondrial membrane?  
 (A) ADP (B) ATP (C) protons (D) neutrons

Output: C


Input: Consider Input: In a northern state, a room used for growing plants is not allowing enough light to enter for healthy plant growth. Adding windows in walls facing which direction would best solve this problem?  
 (A) north (B) south (C) east (D) west

Output: B


Input: Consider Input: When zinc and copper are melted together, brass is formed. Brass is an example of  
 (A) a solute. (B) an element. (C) a mineral. (D) a mixture.


Output: D