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: Gynaecology & Obstetrics
III perineal tear is involvement of : 
Select and explain. 
A. Vaginal mucosa, B. Urethral mucosa, C. Levator ani muscle, D. Anal sphincter
D: Anal sphincter
Answer: D: Anal sphincter 
Explanation: Anal sphincter