**Core Concept**
Phenothiazines are a class of antipsychotic medications that also possess antiemetic properties. They act by blocking dopamine receptors in the chemoreceptor trigger zone (CTZ) of the brain, which is responsible for triggering nausea and vomiting. Additionally, some phenothiazines have a labyrinthine suppressant effect, which can be useful in treating vertigo by reducing the symptoms of inner ear dysfunction.

**Why the Correct Answer is Right**
The correct answer is a phenothiazine with labyrinthine suppressant activity used for treating vertigo. This medication works by blocking the dopamine receptors in the vestibular system of the inner ear, which helps to reduce the symptoms of vertigo. The labyrinthine suppressant effect is thought to be due to the blockade of dopamine receptors on the hair cells of the inner ear, which are responsible for transmitting balance and equilibrium information to the brain.

**Why Each Wrong Option is Incorrect**
* **Option A:** is a medication used for treating schizophrenia, not vertigo.
* **Option B:** is a medication used for treating Parkinson's disease, not vertigo.
* **Option C:** is a medication used for treating motion sickness, not vertigo.

**Clinical Pearl / High-Yield Fact**
The phenothiazines are a class of medications that should be used with caution in patients with a history of glaucoma, as they can worsen intraocular pressure. Additionally, the labyrinthine suppressant effect of these medications can be beneficial in treating vertigo, but it should not be used as a substitute for proper vestibular rehabilitation therapy.

**Correct Answer: C. Scopolamine**