**Core Concept**
The child's presentation is consistent with acute otitis media with perforation of the tympanic membrane, specifically involving the pars flaccida region. This condition is often associated with the presence of a cholesteatoma, a type of skin cyst that can erode bone and lead to hearing loss.

**Why the Correct Answer is Right**
The correct answer is a myringoplasty with mastoid exploration, which is indicated due to the presence of a cholesteatoma. Cholesteatomas require surgical removal to prevent further bone erosion and hearing loss. The procedure involves repairing the tympanic membrane and exploring the mastoid bone to remove any remaining disease. The foul-smelling purulent discharge is indicative of a chronic infection, which requires surgical intervention.

**Why Each Wrong Option is Incorrect**
**Option A:** Antibiotic therapy alone is not sufficient to treat a cholesteatoma, as it is a localized skin cyst that requires surgical removal.

**Option B:** Tympanocentesis may be performed in cases of acute otitis media, but it is not indicated in this case due to the presence of a cholesteatoma.

**Option C:** Corticosteroids may be used to reduce inflammation, but they do not address the underlying cause of the hearing loss, which is the cholesteatoma.

**Clinical Pearl / High-Yield Fact**
Cholesteatomas are often associated with a history of recurrent otitis media or perforation of the tympanic membrane, and may present with hearing loss, ear discharge, or vertigo.

**Correct Answer:** C. Myringoplasty with mastoid exploration.