Task: Question Answering
Input (English): Question: One of the main limitations of the behavioral treatment (exposure with prevention of response) of OCD is: 
 Options:  <1> His recent appearance. <2> The reduced efficacy compared to cognitive and pharmacological treatments. <3> The lack of an explanatory theoretical model. <4> The difficulty of application in cases of motor rituals. <5> The existence of a relevant percentage of patients who reject treatment because of its aversive nature.
Output (English): 5