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: Calcium carbonate (CaCO_{3}) is considered a compound because it is made up of two or more  
 (A) molecules. (B) elements. (C) gases. (D) solids.

Output: B


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: A bicycle is considered a complex machine because it is  
 (A) used to perform a task. (B) made from natural materials. (C) made up of more than one simple machine. (D) complicated to build and repair.


Output: C