**Core Concept:** Enteral nutrition is a method of providing nutrients directly into the gastrointestinal tract via a feeding tube, often used in patients unable to consume food orally. Diarrhea is a common complication of enteral nutrition, and its management is crucial to prevent complications like dehydration and electrolyte imbalances.

**Why the Correct Answer is Right:**

Diarrhea in patients on enteral nutrition can have multiple causes. In this case, the correct answer (d) focuses on the importance of excluding Clostridium difficile in cases of persistent diarrhea. Clostridium difficile is a significant cause of antibiotic-associated diarrhea, and excluding it is crucial for appropriate diagnosis and management.

**Why Each Wrong Option is Incorrect:**

Option A is incorrect because the statement "Diarrhea seen in > 30% cases" is an exaggerated figure, and the actual prevalence varies depending on various factors.

Option B is incorrect because the difference in diarrhea incidence between duodenal and jejunal nutrition is not substantial and should not be a decisive factor for diagnosis or treatment.

Option C is incorrect as the cause of diarrhea in this context is not limited to contamination of the food, and excluding other potential causes is essential before attributing it to contamination.

**Clinical Pearl:**

When managing patients on enteral nutrition who develop diarrhea, it is essential to identify the underlying cause. In cases of persistent diarrhea, excluding Clostridium difficile is crucial to avoid misdiagnosis and inappropriate treatment.

**Correct Answer:**

Correct Answer: D. In persistent diarrhea, clostridium difficile should be excluded.

**Explanation:**

Diarrhea in patients on enteral nutrition is a multifactorial issue, involving factors like the type of feeding tube, speed of feeding, and the patient's individual response to enteral nutrition. However, when diarrhea persists, it is crucial to consider Clostridium difficile as a potential cause, especially in patients who have received recent antibiotic therapy. Excluding C. difficile infection is essential to ensure appropriate diagnosis and treatment, preventing unnecessary antibiotic usage and minimizing the risk of antibiotic resistance.