**Core Concept**
In the treatment of buccal mucosa squamous cell carcinoma with alveolar infiltration, surgical options are chosen based on the extent of bone involvement and the patient's overall health. The goal is to achieve a balance between tumor control and functional and cosmetic outcomes. Segmental mandibulectomy is often preferred for more advanced cases.

**Why the Correct Answer is Right**
Marginal mandibulectomy is a type of surgery that involves removing the outer table of the mandible to access the tumor site. However, in cases where the tumor has infiltrated the alveolus, removing only the outer table of the mandible would not be sufficient to achieve clear margins. This is because the alveolus is a part of the inner table of the mandible, which would remain intact in this procedure. Therefore, **Option C** is incorrect because it does not address the extent of bone involvement.

**Why Each Wrong Option is Incorrect**

**Option A:** Radiotherapy is a valid treatment option for early-stage buccal mucosa squamous cell carcinoma but may not be sufficient for a tumor that has infiltrated the alveolus.

**Option B:** Segmental mandibulectomy is a more aggressive surgical option that involves removing a portion of the mandible, which may be necessary for tumors with alveolar infiltration.

**Option D:** Marginal mandibulectomy involving removal of the upper half of the mandible is a more extensive procedure than necessary for a tumor with alveolar infiltration.

**Clinical Pearl / High-Yield Fact**
When managing oral cavity cancers, it's essential to consider the extent of bone involvement and the patient's overall health when choosing between different surgical options. Segmental mandibulectomy may be necessary for tumors with significant bone invasion, but it's a more complex procedure with potential for significant morbidity.

**✓ Correct Answer: C. Marginal mandibulectomy involving removal of the outer table only**