A grandfather wants Jimmy, his five-year old grandson, to clean his entire room. First, he gives Jimmy a piece of candy for picking up his dirty clothes. Next, he gives him another piece of candy when he puts away his toys. Next, he gives him a piece of candy when he hangs up his clean clothes. Finally, he gives Jimmy candy when he keeps his entire room clean. Jimmy's grandfather is using what operant conditioning technique?
a. shaping
b. token economy
c. coping strategies
d. biofeedback
e. negative reinforcement