**Core Concept:** Acute facial neuralgia is a severe pain in the facial nerve, typically caused by skull base infections or inflammation. In diabetics, these infections can lead to complications such as granulation tissue formation in the ear canal.

**Why the Correct Answer is Right:** The correct answer, **D** (Amikacin), is a type of aminoglycoside antibiotic that has excellent penetration into the cerebrospinal fluid and bone tissue. It has strong activity against Gram-negative bacteria, including Pseudomonas aeruginosa and Haemophilus influenzae, which are common pathogens causing facial neuralgia in diabetic patients.

**Why Each Wrong Option is Incorrect:**

A. **Ibuprofen (Option A):** Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen are not effective for treating bacterial infections and do not address the underlying granulation tissue formation.

B. **Cephalosporins (Option B):** Cephalosporins are a class of broad-spectrum antibiotics, but they are less effective against Gram-negative bacteria, which are commonly involved in facial neuralgia cases.

C. **Dexamethasone (Option C):** Dexamethasone is a corticosteroid used to reduce inflammation, but it does not directly address the bacterial infection causing facial neuralgia and its complications like granulation tissue formation.

**Clinical Pearl:** Granulation tissue formation in the ear canal is a complication of severe facial neuralgia in diabetic patients. Timely and appropriate antibiotic therapy, like Amikacin (Option D), is essential to prevent complications and ensure successful treatment.

**Correct Answer:** Amikacin (D) is the correct treatment choice for this patient, as it effectively targets the common bacterial pathogens (Gram-negative) involved in facial neuralgia and addresses the inflamed granulation tissue.