**Core Concept**
Meniere's disease is a disorder of the inner ear characterized by episodes of vertigo, tinnitus, hearing loss, and a feeling of fullness in the ear. The pathophysiology involves endolymphatic hydrops, where there is an abnormality in the fluid dynamics of the inner ear, leading to the symptoms associated with the disease.

**Why the Correct Answer is Right**
The correct answer, B. Giddiness is provoked in certain head positions, is incorrect because in Meniere's disease, vertigo is typically provoked by changes in head position or motion, but this is not a specific or unique feature of the disease. In fact, vertigo in Meniere's disease is often spontaneous and unpredictable, rather than being specifically triggered by certain head positions.

**Why Each Wrong Option is Incorrect**
**Option A:** Hearing loss that fluctuates is a classic feature of Meniere's disease, which often starts with low-frequency sensorineural hearing loss that fluctuates over time.
**Option C:** Sense of pressure or fullness in the ear is a common symptom of Meniere's disease, often described as a feeling of blockage or fullness in the affected ear.
**Option D:** Roaring tinnitus is a characteristic symptom of Meniere's disease, often described as a low-pitched, roaring sound in the affected ear.

**Clinical Pearl / High-Yield Fact**
A key feature of Meniere's disease is the fluctuating nature of its symptoms, particularly hearing loss, which can improve or worsen over time. This is in contrast to other causes of hearing loss, which may be more permanent.

**✓ Correct Answer: B. Giddiness is provoked in certain head positions**