The answer is C, Clomipramine. The first line treatment for Obsessive Compulsive Disorder includes SSRIs and/or Cognitive Behavioral Therapy. Clomipramine is a serotonergic tricyclic antidepressant that previously was the first line therapy for OCD-- however, SSRIs are more tolerable and safer, and so should be tried first if possible. Clomipramine is the only TCA used to treat OCD. In general, clinicians can opt for pharmacological treatment with high-dose SSRI, CBT specifically designed for OCD, or a combination of both. Clomipramine can also be used to augment SSRIs in treatment-resistant cases.

Publication reference : Fenske JN, Petersen K. Obsessive-Compulsive Disorder: Diagnosis and Management. Am Fam Physician. 2015 Nov 15;92(10):896-903. PubMed PMID: 26554283.
Reference URL: http://www.aafp.org/afp/2015/1115/p896.html