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 is the best evidence for the theory of continental drift?  
 (A) the appearance of volcanoes at the boundaries where plates collide (B) earthquakes at boundaries where one plate slides past another (C) cases where a species exists in only one isolated place (D) fossils of the same species found on widely separated continents

Ex Output:
D


Ex Input:
What causes ocean water to evaporate in the water cycle?  
 (A) energy from the Sun (B) energy from ocean waves (C) energy from Earth's rotation (D) energy from Earth's moon

Ex Output:
A


Ex Input:
Blood is composed of different cell types that transport nutrients and wastes throughout the body. Because of this, blood is classified as  
 (A) a tissue. (B) an organ. (C) a system. (D) an organism.

Ex Output:

A