May's cat runs to the kitchen not only when it hears the electric can opener, but also when it hears may open the cabinet to retrieve the can opener. which alternative identifies the cs (s) for the cat's behavior of running?

CS means conditioned stimuli. So the answer would be the sound of the can opener and the sound of the cabinet door. Conditioned stimuli is a stimuli that is beforehand a neutral stimuli but when linked to the unconditioned stimuli, it then eventually triggered the conditioned response. Since the cat goes to the kitchen when it hears the sound of these two.