Renee Is Scared to Stay Alone at Home, Especially at Night

Renee is scared to stay alone at home, especially at night. She experiences a sense of fear every time she hears a clicking sound and interprets it as the sound made when someone tries to break open a lock. Although her house is in a safe locality and there has never been any instance of burglary, she is still terrified at the thought of someone breaking in. This type of learning is an example of

A) operant conditioning.
B) counter conditioning.
C) systematic desensitization.
D) classical conditioning.