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
A woman delivers a 91b infant with a midline episiotomy and suffers a third degree tear. Inspection shows which of the following structures is intact : 
Select and explain. 
A. Anal sphincter, B. Perineal body, C. Parineal muscles, D. Rectal mucosa
D: Rectal mucosa
Answer: D: Rectal mucosa 
Explanation: Rectal mucosa