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': "The most common coagulation disorders haemophilia A and Von WilLebrand's disease are due to \nSelect and explain. \nA. Factor IX deficiency, B. Vitamin K deficiency, C. Factor X deficiency, D. Factor VIII deficiency", 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]