**Core Concept**
The question is testing the management of squamous cell carcinoma (SCC) of the buccal mucosa, specifically in an edentulous patient with alveolar infiltration. The correct approach involves considering the tumor's location, extent of invasion, and the patient's dental status.

**Why the Correct Answer is Right**
Squamous cell carcinoma of the buccal mucosa is a type of oral cancer that can be challenging to manage, especially in edentulous patients. In such cases, the tumor may infiltrate the alveolar bone, making surgical resection more complex. However, radiation therapy and chemotherapy may still be effective treatment options. The key is to assess the tumor's resectability and the patient's overall health status before deciding on the best course of treatment.

**Why Each Wrong Option is Incorrect**
**Option A:** Radiation therapy is often indicated in cases where surgical resection is not feasible or would result in significant tissue loss. It can be an effective treatment for SCC of the buccal mucosa, especially in edentulous patients.
**Option B:** Chemotherapy may be used as an adjunct to radiation therapy or in cases where the tumor is advanced and not amenable to surgical resection. It can help control the tumor and improve the patient's quality of life.
**Option D:** Surgical resection, including mandibulectomy, may be indicated in cases where the tumor is resectable and the patient's overall health status allows for it. This option is not necessarily incorrect, but rather, it depends on the specific situation.

**Clinical Pearl / High-Yield Fact**
When managing SCC of the buccal mucosa, it's essential to consider the patient's dental status and the tumor's extent of infiltration. A thorough evaluation, including imaging studies and biopsy, is crucial to determine the best treatment approach.

**Correct Answer: A.**