Friday night is dinner night out for sally and harry. when they go to a chinese restaurant, they use chopsticks to eat their noodles. when they go to an italian restaurant they use a fork and a spoon to eat spaghetti. at home, they prefer eating all foods with their hands. although the topography differs, they are functionally equivalent because they all result in getting food in their mouth. these different ways of eating are all part of the same ­

1. topographical response class
2. discriminative stimulus
3. stimulus class
4. response class