Answer:
The correct answer is: Median umbilical ligaments.
After birth, the proximal part of each umbilical artery becomes the median umbilical ligament, a fibrous cord that runs along the inner abdominal wall. The umbilical arteries themselves become obliterated (closed off) and form fibrous cords, while the umbilical vein becomes the ligamentum teres hepatis, which attaches to the liver.
