This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Rectum and anal canal, Subject name: Surgery
[{'content': 'Most common anorectal fistula: \nSelect and explain. \nA. Inter sphincteric, B. Trans sphincteric, C. Supra sphincteric, D. Extra sphincteric', 'role': 'user'}, {'content': "Answer: A \nExplanation: PARK'S CLASSIFICATION Type 1 Inter- sphincteric (MC) Type 2 Trans- sphincteric Type3 Supra- sphincteric Type4 Extra- sphincteric Investigations - First investigation - Fistulogram - IOC- MRI Treatment High morbidity * Fistulotomy -Incision over fistula tract it * Fistulectomy- Excision of fistula tract. * SETON * VAAFT (Video Assisted Anal Fistula Treatment", 'role': 'assistant'}]