This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Development of GU system and Neuro-vascular supply of pelvis & perineum, Subject name: Anatomy
Internal trigone of urinary bladder develops from:- 
Select and explain. 
A. Ectoderm, B. Endoderm, C. Mesoderm, D. Any of above
C: Mesoderm
Answer: C: Mesoderm 
Explanation: The entire mucosa of urinary bladder except the internal trigone develops from endoderm of vesicourethal pa of cloaca. The internal trigone is developed from the mesoderm by incorporation of caudal pas of the mesonephric ducts.