This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anatomy of the female genital tract, Subject name: Gynaecology & Obstetrics
Ligamentum teres is 
Select and explain. 
A. Obliteration of umbilical vein, B. Obliteration of ductus venosus, C. Obliteration of ductus aeriosus, D. Obliteration of hypogastric aery
A: Obliteration of umbilical vein
Answer: A: Obliteration of umbilical vein 
Explanation: Circulatory Changes at Bih:After bih, the umbilical vessels, ductus aeriosus, foramen ovale, and ductus venosus normally constrict or collapse. The more distal poions of the hypogastric aeries, which course from the level of the bladder along the abdominal wall to the umbilical ring and into the cord as the umbilical aeries, undergo atrophy and obliteration within 3 to 4 days after bih. These become the umbilical ligaments, whereas the intraabdominal remnants of the umbilical vein form the ligamentum teres. The ductus venosus constricts by 10 to 96 hours after bih and is anatomically closed by 2 to 3 weeks, resulting in the formation of the ligamentum venosumReference: William&;s Obstetrics; 24th edition; Chapter 7; Embryogenesis and Fetal Morphological Development