What Is the Primary Purpose Behind the Use of Systematic

What is the primary purpose behind the use of systematic desensitization in treatment for paraphilias? 

A)  to produce shame about the paraphilic behaviour 
B)  to switch orgasmic responses to a more socially acceptable source 
C)  to create a sense of relaxation during intense arousing situations 
D)  to decrease the sex drive without the use of drugs