Derek Has Just Invented a New Game to Play with His

Multiple Choice

Derek has just invented a new game to play with his 18-month-old daughter,Beth.In the game,Derek distorts his facial features and makes an unusual noise.Then,it's Beth's turn to do the same thing.This activity,which is enjoyed by both Beth and Derek,illustrates

A) launching.
B) scaffolding.
C) possible selves.
D) negative reinforcement.