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 Q]: 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
[EX A]: B

[EX Q]: A snail's shell provides the snail with  
 (A) food. (B) energy. (C) protection. (D) transportation.
[EX A]: C

[EX Q]: Several dinosaur bones are discovered buried in volcanic ash. The type of dinosaur can best be identified by  
 (A) knowing the location where the fossils were found. (B) establishing an inventory of bones collected. (C) comparing to characteristics of known dinosaurs. (D) knowing the absolute age of the fossils.
[EX A]:
C