adam is upset that his twin brother ryan has two pieces of pie while he only has one. his mom rightly states that it s the same amount of pie it s just that ryan s piece fell apart into two pieces as it was transferred onto the plate. still not satisfied, adam begins to throw a temper tantrum. in a moment of desperation, adam s mom cuts his piece in half saying: there, adam, now you have two pieces! this worked. adam is now happy. what piagetian stage is adam in? a. formal operational b. concrete operational c. preoperational d. sensorimotor