This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Internal sphincterotomy is the treatment of choice for - 
Select and explain. 
A. Piles, B. Fistula, C. Fissure-in-ano, D. Carcinoma
C: Fissure-in-ano
Answer: C: Fissure-in-ano 
Explanation: None