This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Small intestine, Subject name: Surgery
Causes of non-healing of enterocutaneous fistula are all except: 
Select and explain. 
A. Epithelialization of track, B. Radiation enteritis, C. Acute inflammatory disease, D. Track length >3 cm
D: Track length >3 cm
Answer: D: Track length >3 cm 
Explanation: Factors Preventing Spontaneous Fistula Closure High output (>500 mL/day) Severe disruption of intestinal continuity (> 50% of bowel circumference) Active inflammatory bowel disease of bowel segment Cancer Radiation enteritis Distal obstruction Undrained abscess cavity Foreign body in the fistula tract Fistula tract <2.5 cm long Epithelialization of fistula tract