**Core Concept**
Glottic carcinoma is a type of cancer affecting the vocal cords, classified as T1N0M0, indicating a small tumor (T1) without lymph node involvement (N0) and no distant metastasis (M0). The management of early-stage glottic cancer aims to preserve voice function and minimize treatment-related morbidity.

**Why the Correct Answer is Right**
The treatment of choice for T1N0M0 glottic carcinoma is radiotherapy. This is because radiotherapy offers high local control rates, preserves voice function, and has a lower risk of treatment-related morbidity compared to surgical options. Radiotherapy works by delivering high-energy radiation to the tumor site, inducing DNA damage and inhibiting tumor growth. The primary goal is to control the tumor while maintaining the patient's quality of life.

**Why Each Wrong Option is Incorrect**
**Option A:** Surgery is generally reserved for larger tumors or those with significant voice impairment, and may result in temporary or permanent voice changes.
**Option B:** Chemotherapy has limited efficacy in the treatment of early-stage glottic carcinoma and is often reserved for more advanced disease or in combination with radiotherapy.
**Option C:** Chemoradiation may be considered for more advanced disease or in cases of poor response to radiotherapy alone, but is not the first-line treatment for T1N0M0 glottic carcinoma.

**Clinical Pearl / High-Yield Fact**
For early-stage glottic carcinoma, the primary goal of treatment is to achieve local control while preserving voice function. Radiotherapy is the preferred treatment option due to its high efficacy and low morbidity.

**Correct Answer:** A. Radiotherapy.