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: Anatomy
Lateral boundry of ischiorectal fossa is formed by 
Select and explain. 
A. Gluteus maximus, B. Levator ani, C. Gluteus minimus, D. Obturator internus
D: Obturator internus
Answer: D: Obturator internus 
Explanation: Boudaries of ischiorectal fossa
Anterior - Perineal membrane
Posterior - Gluteus maximus
Lateral - Obturator internus
Medial - External anal sphincter and levator ani