**Core Concept**
The patient presents with a midline tumor of the lower jaw, involving the alveolar margin, in an edentulous individual. This scenario suggests a diagnosis of a central, intraosseous jaw tumor, likely a squamous cell carcinoma of the mandible.

**Why the Correct Answer is Right**
The primary treatment for a central, intraosseous jaw tumor is surgical resection, often involving a segmental mandibulectomy. This procedure involves the removal of the affected portion of the mandible, along with some surrounding bone and tissue. The goal is to achieve complete tumor excision while preserving sufficient mandibular height and function to allow for reconstruction and maintain oral competency. The resection may be performed with or without neck dissection, depending on the tumor's extent and the presence of lymph node metastasis.

**Why Each Wrong Option is Incorrect**
**Option A:** Chemotherapy or radiation therapy alone may be used as adjuvant treatment for squamous cell carcinoma of the jaw, but they are not the primary treatment for a central, intraosseous tumor.
**Option B:** Biopsy and histopathological examination are essential for diagnosing the tumor type and grade, but they do not constitute the treatment of choice for this patient.
**Option C:** A radical neck dissection may be indicated in cases of advanced neck metastasis, but it is not the primary treatment for a central, intraosseous jaw tumor.

**Clinical Pearl / High-Yield Fact**
It is essential to distinguish between central and peripheral jaw tumors, as their treatment approaches differ significantly. Central tumors, like squamous cell carcinoma of the mandible, often require surgical resection, whereas peripheral tumors may be managed with more conservative approaches, such as excisional biopsy or radiotherapy.

**Correct Answer:** C. Segmental mandibulectomy