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]: A student notices a paw print while walking in a park. The paw print could be considered a fossil if the print was in ___.  
 (A) rock (B) topsoil (C) thick mud (D) loose sand
[EX A]: A

[EX Q]: Which of the following is the best observation of the refraction of light?  
 (A) Looking at oneself in a mirror (B) Looking at a shadow of an object (C) Viewing an object through an open window (D) Viewing an object partially in water
[EX A]: D

[EX Q]: Most sedimentary rock is made from sediments of other rock. Which of these processes would the sediments most likely go through to form sedimentary rock?  
 (A) compaction and cementation (B) folding and recrystallization (C) melting and solidifying (D) heating and pressure
[EX A]:
A