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': "Von Willebrand's factor is synthesized in which one of the following - \nSelect and explain. \nA. Vascular endothelium, B. Macrophages, C. Liver, D. Eosinophils", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]