Read the excerpt from The Call of the Wild below and answer the question.
With the aurora borealis flaming coldly overhead, or the stars leaping in the frost dance, and the land numb and frozen under its pall of snow, this song of the huskies might have been the defiance of life, only it was pitched in minor key, with long-drawn wailings and half-sobs, and was more the pleading of life, the articulate travail of existence. 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.
In the excerpt above, the author is comparing "wildness" to _____.
a song
a leaping star
the aurora borealis
sobbing and crying