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': 'All of the substances are present in dense granules of platelets, EXCEPT: \nSelect and explain. \nA. Serotonin, B. vWF, C. Calcium, D. ATP', 'role': 'user'}, {'content': 'Answer: B \nExplanation: vWF is released by alpha granules of platelets. Dense granules of platelets: contain the non-protein substances that are secreted in response to platelet activation, including serotonin, ADP, ATP, calcium and polyphosphate.Alpha granules of platelet: contain fibrinogen, fibronectin, vWF, PDGF, EGF, TGF Beta, platelet factor 4, thromboglobulin, albumin, immunoglobulins, antibacterial proteins and a complement inhibitor.', 'role': 'assistant'}]