Okay, let's tackle this question. The question is about the commonest operation for peptic ulcer disease with gastric outlet obstruction. First, I need to recall the standard surgical procedures used for this condition.

Peptic ulcer disease can lead to complications like gastric outlet obstruction, which is often due to scarring and narrowing from chronic inflammation. The main goal of surgery here is to relieve the obstruction and address the underlying ulcer.

The common procedures I remember are vagotomy with pyloroplasty and gastrectomy variations. Vagotomy reduces acid secretion by cutting the vagus nerve, which is part of the parasympathetic nervous system controlling gastric acid. Pyloroplasty then enlarges the pyloric channel to improve gastric emptying. Another option might be a Billroth I or II procedure, which are types of gastrectomy, but those are more for cancer or when there's extensive damage. However, in the case of obstruction without malignancy, vagotomy with pyloroplasty is preferred because it's less invasive and preserves the stomach.

Looking at the options, the correct answer should be Vagotomy with pyloroplasty. The other options might include other procedures like simple vagotomy without pyloroplasty, which wouldn't address the obstruction. Or maybe a gastrojejunostomy, which is a bypass but not the first choice. Also, a Billroth procedure is more involved and not the commonest for this specific scenario.

So, the core concept here is understanding the surgical management of peptic ulcer complications. The key is that vagotomy reduces acid production, and pyloroplasty addresses the mechanical obstruction. The incorrect options would be procedures that either don't address both issues or are more invasive than necessary. The clinical pearl is that vagotomy with pyloroplasty is the preferred operation for this case, not gastrectomy unless there's malignancy or other indications.

**Core Concept**
The management of peptic ulcer disease with gastric outlet obstruction (GOO) involves addressing both ulcer pathophysiology and mechanical obstruction. The most common surgical approach combines acid suppression (vagotomy) with pyloric channel dilation (pyloroplasty) to relieve obstruction and prevent recurrence.

**Why the Correct Answer is Right**
**Vagotomy with pyloroplasty** is the standard operation for peptic ulcer disease with GOO. Vagotomy reduces gastric acid secretion by interrupting the parasympathetic stimulation of the vagus nerve, addressing the ulcer’s etiology. Pyloroplasty widens the pyloric lumen, resolving the mechanical obstruction caused by edema, inflammation, or scarring. This combination avoids the need for gastrectomy while effectively managing both components of the disease.

**Why Each Wrong Option is Incorrect**
**Option A:** Vagotomy alone does not address the mechanical obstruction from pyloric narrowing.
**Option B:** Gastrectomy (e.g., Billroth I/II) is reserved for malignancy or refractory ulcers, not first-line for GOO.
**Option C:** Gastrojejunostomy bypasses the obstruction but does not treat the underlying acid hypersecretion, leading to ulcer recurrence.

**Clinical Pearl / High-Yield Fact**
Vagotomy with pyloroplasty is preferred over antrectomy or gastrectomy in benign peptic ulcer disease with GOO. Remember: **"V

✓ Correct Answer: C. Truncal vagotomy with gastrojejunostomy