Last Year Stacia Went to a Psychologist and Was Cured

Multiple Choice

Last year Stacia went to a psychologist and was cured of her dog phobia.Today,however,while jogging in the park she was overcome with anxiety when she saw a young man jogging toward her with his golden retriever on a leash.What happened to Stacia's dog phobia

A)  It had not been extinguished after all.
B)  It showed spontaneous recovery. 
C)  It showed stimulus generalization.
D)  It showed higher-order conditioning.