**Core Concept**
Meniere's disease is a disorder of the inner ear characterized by episodes of vertigo, tinnitus, hearing loss, and aural fullness. The primary pathophysiology involves abnormal endolymphatic fluid dynamics, leading to inner ear damage and symptoms.

**Why the Correct Answer is Right**
The correct answer is **C. Cochlear implantation**. This is because Meniere's disease primarily affects the endolymphatic system of the inner ear, and cochlear implantation is a surgical procedure that bypasses the damaged inner ear hair cells to directly stimulate the auditory nerve. However, patients with Meniere's disease who have not undergone destruction of their inner ear hair cells may not benefit from cochlear implantation and may experience complications such as electrical stimulation of the residual hearing or increased vertigo.

**Why Each Wrong Option is Incorrect**
* **Option A:** Endolymphatic sac surgery is a viable treatment option for Meniere's disease that involves removal of a portion of the endolymphatic sac to reduce endolymphatic fluid pressure and alleviate symptoms. This option is not correct.
* **Option B:** Intratympanic injections of steroids or gentamicin are considered for patients with Meniere's disease who have failed medical treatment and retain serviceable hearing. This option is not correct.
* **Option D:** Transmastoid labyrinthectomy (removal of the labyrinth) is a surgical option for Meniere's disease that involves removing the affected portion of the inner ear. This option is not correct.

**Clinical Pearl / High-Yield Fact**
Patients with Meniere's disease should be thoroughly evaluated for residual hearing before considering surgical interventions, as the goal is to preserve hearing whenever possible.

**Correct Answer: C. Cochlear implantation**