If the phrase begins with the words "To hasten" or "To infer," it is a(n) phrase.

i believe it is the first choice (1.)

because the major theme is(“both the wild and civilization have rules.”)

and also as u said,( based on what buck learns within the call of the wild, "both the wild and civilization have rules".this is true of humans within society as well.

wheres the passage with the idiom underlined

when u add 2 plus 2 it equalls 4 bc 9 plus ten is zsdfsjnkdfjvnsdnf