Tony's Mother Wants Him to Learn to Play with Other

Multiple Choice

Tony's mother wants him to learn to play with other children. She begins by offering him a quarter whenever he plays with other children nearby, even if he plays by himself. Later, she gives him a quarter only when he plays on the same playground equipment other children are playing on. Finally, she gives him a quarter only if he actually plays with the other children. Tony's mother is demonstrating how to use

A) classical conditioning.
B) second-order conditioning.
C) shaping.
D) stimulus generalization.