Jacob is a 5 year old boy who is experiencing a phobia to insects. This has created problems because he can't play outside for fear of breaking down every time he sees an insect. As a child,
every time Jacob's mother saw an insect, she screamed, which of course frightened Jacob. If we were to diagram this classical conditioning example, the unconditioned stimulus (UCS) is:

a.) mother screaming
b.) child's fear
c.) insect
d.) child's psychiatric history