**Core Concept**
Basilar migraine, also known as basilar-type migraine, is a subtype of migraine headache with aura that involves the vertebral and basilar arteries. This condition affects the brainstem and posterior circulation, leading to a unique set of symptoms. The pathophysiology of basilar migraine involves the activation of trigeminal nerve pathways and the release of vasoactive peptides, which cause vasodilation and inflammation in the affected arteries.

**Why the Correct Answer is Right**
Basilar migraine is characterized by a more severe and prolonged course of symptoms compared to classic migraine. The severity of symptoms in basilar migraine can include visual disturbances, ataxia, dysarthria, and decreased level of consciousness. The sequence of neurologic deficits in basilar migraine typically follows the distribution of the vertebral and basilar arteries, with symptoms often progressing from the brainstem to the posterior cerebral cortex. In contrast, classic migraine typically presents with milder symptoms, such as visual auras and headache.

**Why Each Wrong Option is Incorrect**
**Option A:** While basilar migraine may affect a different demographic, such as young adults and children, the sex of persons affected is not a distinguishing feature between basilar and classic migraine.
**Option B:** The duration of aura can vary between basilar and classic migraine, but it is not the primary distinguishing feature between the two conditions.
**Option D:** The sequence of neurologic deficits is a characteristic feature of basilar migraine, but it is not the primary distinguishing feature between basilar and classic migraine.

**Clinical Pearl / High-Yield Fact**
It is essential to recognize the unique set of symptoms and clinical features of basilar migraine, as it can mimic other neurological conditions, such as stroke or multiple sclerosis. A thorough history and physical examination, combined with imaging studies, are necessary to diagnose basilar migraine accurately.

**✓ Correct Answer: C. Severity of symptoms**