Expression that do not literally mean what they say are called

How are montag and faber opposites of each other? a) montag is a firefighter, therefore it is his job to burn books. faber used to be and english professor, and it was his job to teach students about books. b) montag is passionate and determined, and farber is wise and cautious c) montag is brave enough to steal and illegal book. faber was too afraid to speak up when books started to become illegal. d) all of the answer choices are correct