The Sea Slug,Aplysia,withdraws Its Gills If It Is Squirted with Water.If

The sea slug,Aplysia,withdraws its gills if it is squirted with water.If the squirts continue,as they do in nature,the withdrawal response will diminish.But if the sea slug receives an electric shock after being squirted,the withdrawal of the gills grows stronger.In applying classical conditioning to the example of the sea slug,the withdrawal of the gills to the water is the

A) unconditioned response.
B) unconditioned stimulus.
C) neutral stimulus.
D) conditioned response.