I don’t really understand what a adverb clause is or what it’s asking can somone explain?

The adventures of tom sawyer, chapter 6 (excerpt) what does tom do to get sid’s attention? a) tom lies in bed as he tries to think of an excuse to miss school b) tom knocks a book on the floor to wake sid up c) tom tells sid that he is suffering from an infected toe and a loose tooth d) tom groans and says, “ when i’m gone…”, so sid will call for aunt polly’s how does sid react to tom as he pretends to die? a) so it becomes anxious and asks if tom is dying b) sid knows tom is faking but joins in with tom’s game c) sid takes tom seriously and makes a list of tom’s valuables d) sid knows tom is a lying and immediately runs to tell aunt polly