**Core Concept**
Buerger's disease, also known as thromboangiitis obliterans, is a rare disorder characterized by inflammation, thrombosis, and fibrosis of small and medium-sized arteries and veins. It predominantly affects the limbs, leading to severe pain, gangrene, and potentially, amputation. A key aspect of managing Buerger's disease is to address the underlying pathophysiology, which involves abnormal vasospasm and impaired vasodilation.

**Why the Correct Answer is Right**
Xanthinol nicotinate, a vasodilator, is used to treat Buerger's disease. It acts by increasing cyclic AMP levels in smooth muscle cells, leading to relaxation and vasodilation. This effect helps to alleviate symptoms such as pain and ischemia, which are common in Buerger's disease patients. Xanthinol nicotinate also has antiplatelet properties, reducing platelet aggregation and adhesion, which contributes to its therapeutic efficacy.

**Why Each Wrong Option is Incorrect**
**Option A:** Propranolol, a beta-blocker, would actually worsen Buerger's disease symptoms by further reducing blood flow to the affected areas.
**Option C:** GTN (glyceryl trinitrate) is primarily used for angina pectoris and acute coronary syndrome; it's not a standard treatment for Buerger's disease.

**Clinical Pearl / High-Yield Fact**
It's essential to recognize that Buerger's disease is a smoking-related disease, and smoking cessation is a crucial aspect of management.

**Correct Answer:**
✓ Correct Answer: B. Xanthinol nicotinate