Read this excerpt from The Call of the Wild by Jack London. It was an old song, old as the breed itself—one of the first songs of the younger world in a day when songs were sad. It was invested with the woe of unnumbered generations, this plaint by which Buck was so strangely stirred. When he moaned and sobbed, it was with the pain of living that was of old the pain of his wild fathers, and the fear and mystery of the cold and dark that was to them fear and mystery.

Which type of conflict is shown in the excerpt?

character vs. self
character vs. nature
character vs. character
character vs. society