**Core Concept**
Ivory osteoma is a type of benign bone tumor characterized by its dense, ivory-like appearance on radiographic examination. This condition arises from the abnormal growth of bone tissue, leading to the formation of a hard, white mass that can cause local destruction of surrounding bone.

**Why the Correct Answer is Right**
The correct answer is **C. Maxilla**. Ivory osteomas most commonly occur in the maxilla, specifically in the anterior maxilla, near the canine fossa. This location is thought to be related to the embryological development of the maxilla, where the bone tissue is more prone to abnormal growth. The maxillary location is also more likely to be symptomatic due to its proximity to the nasal cavity and the potential for airway compromise.

**Why Each Wrong Option is Incorrect**
* **Option A:** This is incorrect because while osteomas can occur in the mandible, they are not the most common site for ivory osteomas.
* **Option B:** This is incorrect because although osteomas can occur in the skull, the maxilla is the most common site for ivory osteomas, not the frontal bone.
* **Option D:** This is incorrect because although osteomas can occur in other bones, the maxilla is the most common site for ivory osteomas, not the ulna.

**Clinical Pearl / High-Yield Fact**
Ivory osteomas are often mistaken for other types of bone lesions, such as giant cell tumors or eosinophilic granulomas. However, the characteristic radiographic appearance and location of ivory osteomas can help differentiate them from other conditions.

**Correct Answer: C. Maxilla**