This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Embryology, Subject name: Anatomy
Lower 1/3 of vagina is formed by: 
Select and explain. 
A. Mesonephric duct, B. Paramesonephric duct, C. Sinovaginal bulbs, D. Genital swellings
C: Sinovaginal bulbs
Answer: C: Sinovaginal bulbs 
Explanation: Ans. C. Sinovaginal bulbsUpper 2/3 of vagina- formed by Paramesonephric DuctLower 1/3 of vagina - formed by Urogenital Sinus (Sinovaginal Bulb of Endodermal Sinus)