This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Pathology
[{'content': 'von Willebrand factor is produced by - \nSelect and explain. \nA. Liver, B. Platelets, C. Endothelial cells, D. Spleen', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Von willebrand factor is produced endothelial cells.It is produced to a lesser degree by megakaryocytes. But mainly by endothelial cells Ref:Robbins and Cotran Pathologic basis of disease.South Asia Edition volume 1. Page no.662', 'role': 'assistant'}]