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: Pathology
[{'content': 'A major source of Von Willebrand factor (vWF) - \nSelect and explain. \nA. Erythrocytes, B. Neutrophils, C. Endothelial cells, D. Monocytes', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Circulating factor VIII has two components.\n(a) Factor VIII c \xa0(Procoagulant protein)\n\nThis is the smaller component\nIt is synthesized in the liver (main source) and kidney.\nIt is an intrinsic pathway component required for activation of factor X.\n\n(b) Von willebrand factor (vWF)\n\nThis is the larger component\nIt is produced by endothelial cells (main source) and megakaryocytes.\nIt has two major functions.\n\n\n\nHelps in platelet adhesion by interacting platelet membrane glycoprotein Ib-IX.\n\n\nStabilizes factor VIIIc.', 'role': 'assistant'}]