This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdomen and pelvis, Subject name: Anatomy
True about anal membrane 
Select and explain. 
A. Perforates at 6 weeks, B. Develops from anterior pa of cloacal membrance, C. Lies at proximal pa of proctodaeum, D. Covers urogenital sins
C: Lies at proximal pa of proctodaeum
Answer: C: Lies at proximal pa of proctodaeum 
Explanation: Before the urorectal septum has an oppounity to fuse with the cloacal membrane, the membrane ruptures, exposing the urogenital sinus and dorsal anorectal canal to the exterior. Later on, an ectodermal plug, the anal membrane, forms to create the lower third of the rectum. ref - Semantischolar.org ref - BDC vol2