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': 'Patients with hemophilia a have bleeding disorder because of - \nSelect and explain. \nA. Lack of platelet aggregation, B. Lack of reaction accelerator during activation of factor X in coagulation cascade, C. Neutralization of antithrombin III, D. Release of Thromboxane A2', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Lack of reaction accelerator during activation of factor X in coagulation cascade", 'role': 'assistant'}]