This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
True about umbilical cord 
Select and explain. 
A. Contains 2 umbilcal veins, B. Contains 1 umbilical aery, C. Right umbilical vein disappear, D. Length is 25 - 30 cms
C: Right umbilical vein disappear
Answer: C: Right umbilical vein disappear 
Explanation: Right umbilical vein regresses and left umbilical vein is left, umbilical cord has two umbilical aeries and the left umbilical vein. An average umbilical cord is 55cm long with a diameter of 1-2 cm and 11helices Ref: Gray's 39e/p-210-220