Laura Commands Her New Puppy to "Shake!" Lifts His Paw

Multiple Choice

Laura commands her new puppy to "Shake!" lifts his paw, and then reinforces him. After several repetitions, she merely touches the dogs paw and says "Shake!" and then reinforces the dog. Later on, she merely extends her hand near the dog's paw and says "Shake!" The dog now raises his paw to shake. In training her dog Laura has used the technique called

A) shaping.
B) stimulus generalization.
C) extinction.
D) stimulus discrimination.