This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S., Subject name: Pediatrics
[{'content': 'Which plasma protein is necessary for adhesion of platelets to subendothelial fibres? \nSelect and explain. \nA. Glycoprotein IIb, B. Von Willebrand factor, C. Platelet factor 3, D. Factor X', 'role': 'user'}, {'content': "Answer: B \nExplanation: b. Von Willebrand factor(Ref: Nelson's 20/e p 2386-2390, Ghai 8/e p 349)Von Willebrand factor present in plasma and expressed on endothelium after tissue injury is necessary for platelet adhesion with the help of Gp Ib/IX on platelets.", 'role': 'assistant'}]