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? O coping strategies O shaping biofeedback O token economy O negative reinforcement