Cody Developed a Severe Fear of Flying When He Was

Multiple Choice

Cody developed a severe fear of flying when he was piloting a small plane through some severe turbulence.He has been seeing a therapist,and it appears that his fear response has been successfully extinguished.The therapist used a flight simulator to help Cody practise his piloting skills in a safe setting.However,the first time Cody stepped back into a real plane,his fear returned.What phenomenon does this illustrate

A)  negative reinforcement 
B)  stimulus generalization 
C)  renewal effect 
D)  higher-order conditioning