**Core Concept**
Narcolepsy is a chronic neurological disorder characterized by excessive daytime sleepiness, cataplexy, hallucinations, and sleep paralysis. The underlying pathophysiology involves the degeneration of hypocretin/orexin-producing neurons in the hypothalamus, leading to impaired regulation of the sleep-wake cycle.

**Why the Correct Answer is Right**
The correct answer is related to the absence of a characteristic feature in narcolepsy. Hypocretin/orexin deficiency is a hallmark of the disorder. The correct answer is likely related to a condition that is associated with hypocretin/orexin or its regulation. For example, **Multiple System Atrophy (MSA)** is a neurodegenerative disorder that affects the autonomic nervous system, and it is associated with hypocretin/orexin deficiency.

**Why Each Wrong Option is Incorrect**
**Option A:** Not a characteristic feature of narcolepsy. While it is true that narcolepsy can involve sleep disturbances, this option is too vague.
**Option B:** Actually seen in narcolepsy. Cataplexy is a characteristic feature of narcolepsy, involving sudden loss of muscle tone triggered by strong emotions.
**Option C:** Not typically associated with narcolepsy. This option may be a distractor, but it is not directly related to the core concept of narcolepsy.

**Clinical Pearl / High-Yield Fact**
Narcolepsy is often associated with other sleep disorders, such as sleep apnea and restless leg syndrome. It is essential to consider these comorbidities when diagnosing and managing patients with narcolepsy.

**Correct Answer:** B. Cataplexy is actually seen in narcolepsy.