**Core Concept**
The treatment of choice for stage III carcinoma of the maxillary sinus (T3 M0 N0) depends on the tumor's extent and the patient's overall health. In this stage, the tumor has grown beyond the maxillary sinus and may have invaded surrounding structures, but there is no distant metastasis or regional lymph node involvement.

**Why the Correct Answer is Right**
The treatment of choice for stage III carcinoma of the maxillary sinus is a combination of surgery and radiation therapy. The tumor's extent and the patient's overall health dictate the need for a multidisciplinary approach. Surgery is typically performed to remove the tumor and surrounding tissues, while radiation therapy is used to eliminate any remaining cancer cells. This approach helps to improve local control and survival rates.

**Why Each Wrong Option is Incorrect**
**Option A:** Chemotherapy alone is not sufficient to treat stage III carcinoma of the maxillary sinus, as it may not effectively target the tumor's extent and surrounding structures.

**Option B:** Photodynamic therapy is not a standard treatment for stage III carcinoma of the maxillary sinus, and its effectiveness in this setting is not established.

**Option C:** Stereotactic radiosurgery is not typically used as the sole treatment for stage III carcinoma of the maxillary sinus, as it may not provide adequate local control and may not address the tumor's extent.

**Clinical Pearl / High-Yield Fact**
The treatment of carcinoma of the maxillary sinus is often individualized and depends on the tumor's extent, the patient's overall health, and the availability of specialized care. A multidisciplinary approach that includes surgery, radiation therapy, and chemotherapy may be necessary to achieve optimal outcomes.

**Correct Answer:** C.