Okay, let's tackle this question. The patient is post-op with peritonitis and a duodenal leak. So, peritonitis from a duodenal leak is a big deal. I need to remember the management for such cases.

First, peritonitis from a leak, especially in the abdomen, is usually a surgical emergency. The main goals are to control the source of infection and manage the infection. Duodenal leaks are high-output and high-risk because of the bile and pancreatic enzymes involved. So, the management would involve surgical intervention to close the leak or divert it, along with broad-spectrum antibiotics.

Looking at the options, the correct answer is likely surgical exploration and drainage. But wait, sometimes in cases of peritonitis, you might do a laparotomy to clean the abdomen and remove the source. Duodenal leaks might require a surgical repair or even a bypass if the damage is severe. Also, peritonitis from a duodenal leak can lead to sepsis quickly, so timely intervention is crucial.

Now, why would other options be wrong? Let's think. If an option suggests conservative management like antibiotics alone, that's incorrect because peritonitis from a leak needs surgical intervention. Similarly, if an option mentions waiting for spontaneous resolution, that's not right. A duodenal leak could lead to abscess formation or septic shock if not addressed. Another option might be a specific procedure like endoscopic stenting, but I'm not sure if that's applicable here. Surgical intervention is the mainstay here.

Clinical pearls: Duodenal leaks are high-output and require early surgical intervention. The key is to control the source and manage the infection aggressively. Also, peritonitis from a leak is a surgical emergency. So the management of choice is surgical exploration and drainage. The correct answer would be the option that states surgical exploration and drainage.

**Core Concept**
Peritonitis due to a duodenal leak is a surgical emergency requiring source control and aggressive management. The duodenum's high-output content of bile, pancreatic enzymes, and acidic chyme leads to rapid peritoneal contamination, necessitating prompt intervention to prevent sepsis and multiorgan failure.

**Why the Correct Answer is Right**
The management of choice involves **surgical exploration and drainage** (e.g., laparotomy) to remove infected material, repair or divert the leak, and achieve peritoneal lavage. Duodenal leaks are high-output and high-risk due to the chemical toxicity of pancreatic enzymes and bile, which cause severe peritoneal inflammation. Source control is critical to prevent septic shock and mortality.

**Why Each Wrong Option is Incorrect**
**Option A:** *Conservative management with antibiotics alone* is incorrect because peritonitis from a duodenal leak requires surgical intervention to control the source.
**Option C:** *Endoscopic stenting* is not effective for peritonitis caused by a large leak or extensive contamination.
**Option D:** *Observation without intervention* is contraindicated due to the high mortality risk of untreated peritoneal sepsis.

**Clinical Pearl / High-Yield Fact**
Duodenal leaks are surgical emergencies; delay increases mortality. Always prioritize source control (surgical exploration) over antibiotics alone in peritonitis from a gastrointestinal leak. Remember the **"ABC" of peritonitis management**:

✓ Correct Answer: B. Duodenostomy + Feeding jejunostomy + Peritoneal lavage