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': 'In which of the following organs are fenestrated endothelial cells common? \nSelect and explain. \nA. Hea, B. Liver, C. Lungs, D. Pancreas', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Fenestrated ("windowed") endothelial cells, which permit free flow of serum across the endothelium, are an unusual feature of the hepatic sinusoids. They are not seen in the other organs listed.', 'role': 'assistant'}]