This question is based on the following information. The Call of the Wild is a novel by Jack London. It focuses on the life of Buck, a pampered dog who lives with a wealthy family in southern California. During the Gold Rush, Buck is captured, sold, and eventually shipped to Alaska. Along the way, Buck is mistreated, but eventually he learns to survive as a member of a dog sled team. With each new experience, Buck becomes more acquainted with his ancestor's instincts. Finally, after losing someone he cared about, Buck decides to return to living in the wild.
Which of these statements best represent the theme of The Call of the Wild?
A. A dog is mistreated for his entire life, even as part of a dog sled team.
B. A dog learns what it's like to be taken from his home and sent far away.
C. A dog discovers the differences between life in California and in Alaska.
D. A dog endures hardship but ends up going back to where he is meant to be.