Read the sentence, and then identify its error by selecting the appropriate answer choice. It can be a real challenge to make a lunch that are both healthy and tasty.
OIt can be
Oreal challenge
O to make
Othat are

It'd be D, that are, because it should be:

"It can be a real challenge to make a lunch that is both healthy and tasty"

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.