This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdomen: Miscellaneous, Subject name: Anatomy
All are true about Diploic veins EXCEPT: 
Select and explain. 
A. Lined by single layer endothelium suppoed by elastic tissue, B. Present in Cranial bones, C. Valveless, D. Develop by 8th week of IUL
D: Develop by 8th week of IUL
Answer: D: Develop by 8th week of IUL 
Explanation: Diploic veins sta developing in the cranial bones at about 2 years of age and are fully developed at the age of 35 years. These are lined by a single layer endothelium suppoed by elastic tissue and are valveless.