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: Rock layers with sand-sized particles were most likely deposited by  
 (A) wind. (B) water. (C) glaciers. (D) landslides.
Example Output: A

Example Input: A scientist studies the remains of two extinct animals to learn more about how they lived. She determines that one animal was a carnivore and the other was an herbivore. Which of the following did the scientist most likely compare to make this conclusion?  
 (A) the number of bones in the animals (B) the size of the animals (C) the body covering of the animals (D) the skull of the animals
Example Output: D

Example Input: Earth is composed of layers of material with different properties. Which of the following is most likely to be in constant motion?  
 (A) core (B) mantle (C) oceanic crust (D) continental crust
Example Output:
B