**Core Concept:** Transient Ischemic Attack (TIA) and Stroke, their pathophysiology and clinical presentation.

**Why the Correct Answer is Right:**
The correct answer is **Option C: Stroke**, specifically an ischemic stroke (also known as cerebral infarction) caused by occlusion of a cerebral artery. Sudden onset drooping of the right face (Facial Dysesthesia) and hemiplegia (loss of muscle function on one side of the body) are common clinical presentations in ischemic stroke. The affected individual would also likely experience altered consciousness, seizures, and/or sensory deficits depending on the affected area. These symptoms are usually brief, lasting less than 24 hours, which differentiates them from a stroke with permanent damage (stroke).

**Why Each Wrong Option is Incorrect:**
A. Transient Ischemic Attack (TIA) shares some clinical similarities with stroke but is a temporary episode of neurological dysfunction caused by transient cerebral ischemia. Unlike stroke, TIA symptoms resolve within minutes to hours without causing permanent brain damage.

B. Subarachnoid haemorrhage (SAH) causes a sudden onset of severe headache, often described as "the worst headache of one's life," nausea, vomiting, and sometimes focal neurological deficits or altered consciousness. SAH is a result of bleeding into the subarachnoid space, not related to facial drooping and hemiplegia.

D. Encephalitis causes inflammation of the brain and presents with varied neurological symptoms, not specifically facial drooping and hemiplegia. Encephalitis can present with fever, seizures, cognitive deficits, and psychiatric disturbances.

**Clinical Pearl:**
A 50-year-old hypertensive patient presenting with sudden onset facial drooping and hemiplegia warrants a high degree of suspicion for stroke, particularly an ischemic stroke, and immediate neuroimaging is essential to confirm the diagnosis and initiate timely management.