**Core Concept:** Obsessive-Compulsive Disorder (OCD) is a psychiatric disorder characterized by unwanted and repetitive thoughts (obsessions) and/or actions (compulsions) that the individual feels compelled to perform due to anxiety or distress. OCD symptoms typically involve excessive cleanliness, checking, ordering, and washing behaviors.

**Why the Correct Answer is Right:** The correct answer is D (Fluvoxamine), which belongs to the selective serotonin reuptake inhibitor (SSRI) class of antidepressants. Fluvoxamine works by increasing the levels of serotonin in the brain, which helps in alleviating symptoms of OCD, including excessive cleaning, checking, ordering, and washing behaviors.

**Why Each Wrong Option is Incorrect:**
A. This answer is incorrect as the drug belongs to the benzodiazepine class, which primarily targets the GABAergic system. While some benzodiazepines might be used to treat anxiety disorders, they are not specifically effective for treating OCD symptoms.

B. This answer is incorrect as the drug belongs to the tricyclic antidepressant class, which primarily targets the monoamine neurotransmitters. While tricyclic antidepressants can be used to treat depression and anxiety, they are not specifically effective for treating OCD symptoms like SSRIs.

C. This answer is incorrect as the drug belongs to the antipsychotic class, which primarily targets the dopamine system. Antipsychotics are primarily used for treating psychotic symptoms, not OCD symptoms.

**Clinical Pearl:** Obsessive-Compulsive Disorder is a common psychiatric disorder that affects approximately 1-2% of the general population. Early diagnosis and treatment with appropriate medication, like SSRIs, can significantly improve the patient's quality of life and reduce the risk of complications associated with uncontrolled symptoms.

**Correct Answer Explanation:** Fluvoxamine (Option D) is a selective serotonin reuptake inhibitor (SSRI) that works by inhibiting the reuptake of serotonin, which leads to increased synaptic serotonin levels. This helps to alleviate OCD symptoms such as excessive cleaning, checking, ordering, and washing behaviors.

**Why Fluvoxamine is the right choice:** Fluvoxamine is a selective serotonin reuptake inhibitor (SSRI) that inhibits the reuptake of serotonin, leading to increased synaptic serotonin levels. This helps to alleviate symptoms of obsessive-compulsive disorder (OCD), including excessive cleaning, checking, ordering, and washing behaviors.

**Why other options are wrong:**

A. Clonazepam (Option A) is a benzodiazepine that targets the GABA system, which is primarily involved in anxiety disorders, not OCD symptoms.

B. Amitriptyline (Option B) is a tricyclic antidepressant that targets the monoamine neurotransmitters, primarily affecting serotonin, norepinephrine, and dopamine, which is not specific to OCD symptoms.

C. Haloperidol (Option C) is an atypical antipsychotic that primarily