Gabe Is Trying to Get His Dog, Trixie, to "Sit

Multiple Choice

Gabe is trying to get his dog, Trixie, to "sit up." He starts rewarding her first when she lies down. Then he rewards her when she is sitting on her backside. And finally he rewards her only when she sits up with her paws off the ground. Gabe got Trixie to "sit up" by using

A) shaping.
B) secondary reinforcement.
C) backward conditioning.
D) stimulus discrimination.