Answer:
A. the visit
Step-by-step explanation:
2-year-old Eli’s grandmother gives him a Tootsie roll every time she visits. When Eli sees his grandmother arriving, he begins to salivate. In this example, the conditioned stimulus (CS) is the visit.
In classical conditioning, an unknown/unconditioned stimulus (Tootsie roll) is associated with a conditioned stimulus (grandma's visits) in other to elicit a conditioned response (salivation).