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:
Which best explains how nutrients get into soil?  
 (A) through exposure to air (B) by absorbing sunlight (C) through decaying matter (D) by rocks eroding

Ex Output:
C


Ex Input:
Which explains how the epithelium offers protection to land-dwelling vertebrates?  
 (A) Epithelium provides a rigid shell to prevent punctures. (B) Epithelium has capillaries to resist iron deficiency. (C) Epithelium insulates the vertebrate from hypothermia. (D) Epithelium prevents dehydration in vertebrates.

Ex Output:
D


Ex Input:
Bats find their prey at night using one of their senses to detect echoes. What does the bat send out to find prey?  
 (A) odors (B) light (C) sound (D) electricity

Ex Output:

C