**Core Concept**
Clozapine is an atypical antipsychotic medication primarily used in the treatment of schizophrenia, particularly in patients who have not responded to other treatments. Its unique pharmacological profile sets it apart from typical antipsychotics, with a lower risk of extrapyramidal side effects (EPS) but also distinct adverse effects.

**Why the Correct Answer is Right**
Clozapine is known to cause excessive salivation, leading to sialorrhea, a condition characterized by drooling. This is thought to be due to its antimuscarinic properties, which can cause an increase in parasympathetic tone, resulting in excessive salivation. The antimuscarinic activity of clozapine is mediated through its blockade of muscarinic acetylcholine receptors in the salivary glands, leading to an increase in saliva production.

**Why Each Wrong Option is Incorrect**
**Option A:** Hypertension is not a common adverse effect of clozapine. While antipsychotics can cause orthostatic hypotension, clozapine is not typically associated with hypertension.
**Option C:** Extrapyramidal side effects (EPS) are actually less common with clozapine compared to typical antipsychotics, making this option incorrect. Clozapine's lower risk of EPS is one of the reasons it is often used in patients who have experienced EPS with other antipsychotics.
**Option D:** Neuroleptic malignant syndrome (NMS) is a rare but life-threatening adverse effect of antipsychotic medications, including typical and atypical antipsychotics. However, it is not a specific adverse effect of clozapine.

**Clinical Pearl / High-Yield Fact**
It is essential to monitor patients taking clozapine for signs of sialorrhea, as it can lead to social and emotional distress. Additionally, clozapine can cause other antimuscarinic side effects, such as dry mouth, blurred vision, and constipation, which should be monitored and managed accordingly.

✓ Correct Answer: B. Sialorrhea