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.

Ex Input:
What has occurred when bubbles form in a liquid that is being heated?  
 (A) Oxygen is absorbed from the air. (B) Heat is radiating in the liquid. (C) The boiling point has been reached. (D) Molecular stability in the liquid is increasing.

Ex Output:
C


Ex Input:
Why would animals most likely have to leave an area during a drought?  
 (A) to find mates (B) to find shelter (C) to escape predators (D) to find water and food

Ex Output:
D


Ex Input:
Which of these is a freshwater reservoir?  
 (A) Gulf of Mexico (B) Pacific Ocean (C) Atlantic tidal basin (D) Antarctic polar ice

Ex Output:

D