**Core Concept**
The question is testing the knowledge of the pharmacological management of obsessive-compulsive disorder (OCD), a common psychiatric condition characterized by recurring, intrusive thoughts (obsessions) and repetitive behaviors (compulsions). The correct treatment involves medications that modulate serotonin levels in the brain, as serotonin dysregulation is thought to contribute to the pathophysiology of OCD.

**Why the Correct Answer is Right**
The drug of choice in OCD is a selective serotonin reuptake inhibitor (SSRI), which works by increasing the concentration of serotonin in the synaptic cleft. This is achieved by blocking the reuptake of serotonin by the presynaptic neuron, thereby increasing the amount of serotonin available for binding to postsynaptic receptors. The increased serotonin levels in the brain help to reduce the symptoms of OCD by modulating the activity of the orbitofrontal cortex and basal ganglia, which are involved in the pathophysiology of OCD.

**Why Each Wrong Option is Incorrect**
**Option A:** is incorrect because it is a tricyclic antidepressant, which is not the first-line treatment for OCD. While tricyclic antidepressants can be effective in treating OCD, they are associated with more side effects and are not as well-tolerated as SSRIs.
**Option B:** is incorrect because it is a typical antipsychotic, which is not effective in treating OCD. Antipsychotics may even worsen OCD symptoms in some cases.
**Option C:** is incorrect because it is a monoamine oxidase inhibitor (MAOI), which is not a first-line treatment for OCD due to its dietary restrictions and potential for drug interactions.

**Clinical Pearl / High-Yield Fact**
SSRIs are the first-line treatment for OCD due to their efficacy, tolerability, and safety profile. When choosing an SSRI, it's essential to consider factors such as patient compliance, potential side effects, and drug interactions.

**Correct Answer:** C. Fluoxetine.