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]: Some birds fly south in the fall and return in the spring. This is an example of  
 (A) migration (B) camouflage (C) hibernation (D) growth
[EX A]: A

[EX Q]: A student wants to organize a group of animals into two categories based on observable external features. Which display will most appropriately show the two categories of animals?     
 (A) a timeline (B) a pie chart (C) a data table (D) a line graph
[EX A]: C

[EX Q]: Which object in the sky is a satellite of the planet Earth?  
 (A) Sun (B) Moon (C) Mars (D) Saturn
[EX A]:
B