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.

Example Input: Which is a way the agricultural biotechnology industry could have a positive impact on the environment?  
 (A) by producing crops that are virus resistant (B) by making robots to replace large farm machines (C) by reducing the need for countries to import food (D) by increasing the use of wind farms that produce electricity
Example Output: C

Example Input: Which adaptation helps a bird fly?  
 (A) larger feet (B) bigger eyes (C) longer beaks (D) hollow bones
Example Output: D

Example Input: Two atoms of oxygen combine to form pure oxygen gas. What is the electrical charge of the O_{2} molecules?  
 (A) positive (B) negative (C) neutral (D) variable
Example Output:
C