This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
[{'content': 'All of the following are true about diploic vein except - \nSelect and explain. \nA. Lined by single layer of endothelium supported by elastic tissue, B. Present in cranial bones, C. Valveless / thin walled, D. Develop by 8th week of IUL', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The skull is unilamellar at birth with out any diploe and diploic veins which start to develop at around 2 years after birth.\n\n\nCharacteristic features of the diploic vein are:-\n\n\nAbsent at birth starts appearing around 2 years of age, appears at 4th year, and maximally differentiated by the 35th year\xa0when these are quite prominent radiologically.\nPresent in the diploe of the cranial vault. The major diploic veins are 1) Frontal, 2) Occipital, 3) Anterior and posterior temporal (parietal).\nWall is very thin consisting of endothelium supported by some elastic tissue.\nAre valveless, as are other intracranial veins.', 'role': 'assistant'}]