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
Most common anorectal fistula: 
Select and explain. 
A. Inter sphincteric, B. Trans sphincteric, C. Supra sphincteric, D. Extra sphincteric
A: Inter sphincteric
Answer: A: Inter sphincteric 
Explanation: 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