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:
Plants growing in a pond release a gas that fish need to survive. Which gas do the plants release that fish use?  
 (A) helium (B) hydrogen (C) nitrogen (D) oxygen

Ex Output:
D


Ex Input:
Which location on Earth receives the most direct sunlight?  
 (A) the deserts (B) the South Pole (C) the equator (D) the Western Hemisphere

Ex Output:
C


Ex Input:
Which statement best identifies a living thing that depends on another living thing to survive?  
 (A) A wolf drinks water. (B) A moose eats a plant. (C) A spruce tree grows in soil. (D) A salmonberry plant absorbs sunlight.

Ex Output:

B