Answer:
D. habituation.
Explanation:
Glinda jingles her keys in front of baby Elphaba's face, and she watches and smiles. Glinda continues to bring her keys up and jingle them in front of Elphaba because she appears to enjoy this game. After a while, though, Elphaba seems to lose interest in the game and no longer focuses on the keys when Glinda jingles them. This illustrates the process of habituation.
Habituation in infants is the reduced responsiveness experienced in children after the repeated presentation of a stimulus. After a stimulus is repeated to an infant, the infant becomes desensitized to that stimulus.
