Mr. sampson's mouth always waters when he sees a donut. he nearly always orders a coffee when he has a donut. one day, he orders a coffee and a chocolate donut. he is served the coffee right away, but told that the donuts are still being made and he will have to wait a few minutes. he takes a seat while he is waiting and takes a deep sniff of his coffee. as he does so, a small pile of saliva falls on the table. in terms of classical conditioning, why did this happen?