**Core Concept**
A carotid body tumor is a benign neoplasm arising from the carotid body, a small organ located at the bifurcation of the common carotid artery. The carotid body plays a crucial role in detecting changes in blood pressure, oxygen levels, and pH. Surgical excision is the primary treatment option for carotid body tumors due to their slow growth rate and potential for local invasion.

**Why the Correct Answer is Right**
Excision of the tumor is the preferred treatment because it offers a high chance of cure, especially if the tumor is small and localized. The surgical approach involves a careful dissection of the tumor from the surrounding structures, including the carotid artery, internal jugular vein, and vagus nerve. A thorough preoperative evaluation, including imaging studies and angiography, helps in planning the surgical approach. The goal of surgery is to remove the tumor completely while preserving the surrounding vital structures.

**Why Each Wrong Option is Incorrect**
**Option B:** Radiotherapy is not the primary treatment for carotid body tumors as they are benign and do not typically respond to radiation therapy.
**Option C:** Chemotherapy is not indicated for carotid body tumors as they are not malignant and do not require systemic treatment.
**Option D:** Carotid artery ligation both proximal and distal to the tumor is not a recommended treatment as it can lead to significant complications, including stroke, and is not a definitive treatment for the tumor.

**Clinical Pearl / High-Yield Fact**
It is essential to note that carotid body tumors can be associated with multiple endocrine neoplasia (MEN) syndrome, particularly MEN2A. Therefore, a thorough family history and genetic evaluation should be performed in patients with carotid body tumors.

**Correct Answer:**
✓ Correct Answer: A. Excision of tumor